A far better reason to leave out Mineta's testimony is that he was, and possibly remains to this day, entirely mistaken about his own timeline, and consequently the correct interpretation of what he observed.
Let's start at the end: Mineta's belief that this "The plane is 50 / 30 / 10 miles out" was reporting on "The flight that came into the Pentagon" as Mineta was in the "Presidential Emergency Operating Center" (PEOC). Mineta for himself has worked out his timeline backwards from there. He thinks that, since he was in the PEOC as AA77 was still 30, 50 miles out, he must have arrived in the PEOC well before AA77's crash time, which was 9:37. So, his story goes, he was there at 9:20. Which would imply that Cheney and entourage, too, were there at, even before 9:20.
None of that comes even close to being correct.
Here is Mineta's true timeline, from memory, as best as can be reconstructed from evidence:
9:03: He is at the Department of Transportation, several blocks away from the White House, with his colleague from Belgium, as UA175 crashes into the South Tower on live TV, which is switched on and being noticed since news of the first crash and fire in the WTC were broadcast around 8:50.
9:04: Realizing that something major is amiss, he interrupts the meeting with the Belgian secretary of transport, goes to his office, confers with staff, learns that commercial planes are involved, calls a couple of airline CEOs (I am asking myself as I write this if he knew already which two airlines lost planes at the WTC, which would put a limit on when, at the earliest, he made those calls), etc, then talks with the White House and gets advised to go there ASAP. So he goes downstairs several floor to get into his car with chauffeur.
We can take guesses as to how long all this took, and how long one drives from the Department to the White House, but it is clear already that "9:20" or anything not long after that is quite impossible.
Mineta arrives at the White House perimeter as it is obviously it's being evacuated - many people are walking moving swiftly away from it, he notices. This information allows us to place him at the WH perimeter at or around 9:45. Note that this is already minutes AFTER AA77 crashed into the Pentagon, news of which took several minute to emerge on the news. As none of Mineta's accounts mention him receiving that news as he was on his way to the White House or the PEOC, we may safely infer he didn't hear of it at all until he finally was in the PEOC.
Mineta then first goes to see Richard Clarke, the White House anti-terrorism "czar", who was retained from the Clinton administration. Clarke was in the West Wing, Situation Room or next to it, in a secure video conference. "Secure" means that you could not simply walk in and out, there was a procedure to informationally "sanitize" those who participated on video, so add minutes for Mineta to get physically to Clarke, minutes more where the two talked, minutes more to physically get out. And only THEN did he, with the help of Secret Service agents, eventually move to the PEOC - which is deep below the East Wing, so again a bit of a distance to walk, a couple of minutes at least.
Add all this together, and we are easily past 10 a.m.
Now there exists further documentation of when the others, particularly Cheney, went to the PEOC. This much can be pinned down:
Cheney was in his office until less than a minute before AA77 crashed, and was then grabbed by his Secret Service detail and rushed towards the PEOC.
Plenty of documentation from participants and Secret Service logs exists that agrees Cheney and entourage did not immediately enter the PEOC proper (a conference room with adjacent room for staffers working secure information sources), but were held up in the tunnel leading to it, where there was already a secure phone which Cheney used to talk to the President. This took a few minutes, during which time several people arrived, such as Condolezza Rice or Cheney's wife Lynne. It was there they first learned of the crash of AA77. Only then - the 9/11 Commission estimates around 9:58 - did they move on to the PEOC proper.
There exists a batch of publicly released photos by the Vice Presidents personal photographer, David Bohrer, showing Cheney in his office, then in the PEOC all day. These photos have been analysed in fine detail (I have done a lot of analysis myself), as some can be timestamped to the precise minute, even second, either because there is a readable watch or clock in it, or because a live TV screen shows a scene that can be synchronized with existing archives of the day's news channel broadcasts. From this we know that Cheney, Rice, Mrs Cheney and staffers were first in a "virgin" PEOC (cookie trays, notepads and pens on the tables untouched, no personal notes, folders or other items laying around) at 10:03 - coincidentally the time when the last plane crashed.
Mineta is not seen yet!
Mineta is actually photographed coming in several photos after 10:03, and some photos before one that can be timestamped to 10:18 as per Scooter Libby's watch (the photos themselves are numbered by a system that obviously has a number for the physical analogue film (36 frames) plus a number from 1-36 for the frame on the film - or sometimes 1A-36A - these alternative numbers with a capital "A" indicate that, as happens, the film is shifted such that it would not be clear if an exposure is in the 2 or 3 position, it's halfway between the two, and so on the other side of the film role, there is the 0A to 36A numbering that's shifted by half a frame; this is how we know the metadata on the published digital photos reflects a physical position on film, and thus a temporal order of the exposures).
Mineta never mentions having been held up in the tunnel before proceding to the PEOC proper, he tells how he got the PEOC and the Cheneys and Rice were already there.
So this is how we know he arrived in the PEOC after all planes had crashed - most likely around 10:10 +/- 5 minutes.
So what was this "50/30/10 miles out" scare that he was overhearing in the PEOC?
-> A confusion.
It was a flight plan for UA93, the plane that crashed near Shanksville, extrapolated by a system called "Traffic Situation Display" (TSD), if memory serves (it's one of those terms that I have memorized wrong before, which makes it impossible for me to ever be sure I now remember correctly; at any rate, for the purpose of this post, I'll stick with "TSD"). Here is what happened:
When air traffic controllers (ATC) working UA93 noticed it was unresponsive and had turned, they correctly surmised it was hijacked and the hijackers were heading towards the Washington, DC area. Now, commercial flights submit a flight plan to the FAA's air traffic control system, to allow controllers to extrapolate where planes may show up in the near future. And so, to assist the ATC in the DC sector, some ATC in the Pittsburgh area entered a new flight plan for UA93, which would start at its current location, neat Pittsburgh somewhere, and go to Reagan National Airport, the one that's just a mile and a bit from the Pentagon.
Flights are displayed on the TSD system because that system works with flight plans and simply computes where planes are. And the staffer in the PEOC, perhaps being unaware of what TSD is, what it shows and what it doesn't show, was monitoring this projected flight path of UA93 on TSD and calling out distances to the Pentagon. If I remember correctly, it would have landed at Reagan Natl at 10:28 as per TSD, and so, if Mineta was at the PEOC at 10:10, 18 minutes or 0.3 hours earlier, he indeed might first have heard a distance of "50 miles".
Of course, unbeknownst to the people in the PEOC and also to the TSD, UA93 had, in reality, crashed at 10:03. It was only a computed extrapolation that had it continuing on to the Pentagon.
When it "landed" at Reagan Natl at 10:28 (or whatever the correct time), it "disappeaerd" from TSD. As the destination is right next to the Pentagon, it is perhaps understandable that Mineta might have believed that they were watching the flight the crashed into the Pentagon.
And this is how come Mineta believed, at the 9/11 Commission hearings, and still years later when interviewed, that he was in the PEOC when the Pentagon was impacted. He must have worked out his personal timeline from there - and it was wrong by about 50 minutes.
Mineta was informed at the PEOC that underlings at the FAA had instituted a national ground stop and started to bring down ASAP all flights currently airborne at their nearest feasible air strips. he mistook this for underlings suggesting it, and him making that decision.
Mineta, in short, was unavailable as the disaster unfolded, and could not be reached for the most urgent information and decisions. Like other high ranking officials, he was, essentially, a failure on 9/11.
