Mr. Mierzejewski may have had a good view of Mr. Bush’s airplane, but he wasn’t actually IN that airplane. It’s always been easy to second-guess and criticize the guy in the hot seat.
I’ve known the elder Bush bailed out in WWII, but to be truthful I’m not famillar with the details. However, speaking as a pilot who was once forced down (by weather, not bullets, and no one got hurt) there is ALWAYS someone who is going to say you screwed up, made the wrong choices, were criminally stupid/irresponsible, and should have done 14 other things regardless of the outcome of the choices you actually made.
What damage was actually done to Mr. Bush’s airplane? Did he retain control over it? If the damage was such that he couldn’t control the airplane then waiting to bail benefits no one. Was there fire? Could there be extensive fire on the interior that does not show on the outside, at least at first?
Parachutes DO fail. It is entirely plausible that two men jumped but only one 'chute worked.
Why did Mr. Bush say the third crewman was dead? Could he see the man at all? Were there rivers of blood flowing through the airplane, or geysers of it on the wall whereby one could assume someone was mortally injured? Did the second crewman (with the failed 'chute) tell him the third man was dead?
How reliable is Mr. Mierzejewski’s memory? Could his attention been so fixated on the image of the first man to jump that he didn’t see the second? And, yes, is there any possibility of bias on the part of Mr. Mierzejewski?
Did Bush have an incentive to lie? Hmmm… well, yeah, IF he bailed early and unnecessarialy but are there any indications that he did? I presume you aren’t handed a medal two minutes after being fished out of the Pacific, so someone else must have been convinced of the veracity of his tale. And it’s not like 19/20 year old Bush would have much in the way of pull - no one, at the time, knew he’d wind up PotUS one day. You have to weigh that against other factors, like how likely it would be that a WWII era pilot would panic and bail, and the fact that going swimming in an open ocean during combat means you might not ever be picked up and rescued. If you want to get out of the combat area and go home you’re almost always better sticking with the airplane - unless it really is on fire or irrevocably going down.
And how well did Mr. Bush know his crewmembers, and how well did they all get along? If they were all the best of friends the scenario of abandonment becomes even less likely.
And while it is true that there is an “unwritten rule” that the aircraft pilot takes care of all aboard before taking care of himself, there is no obligation to go down with the ship if he really can’t do anything more about the situation. In the air, an emergency frequently gives you only seconds to make decisions and act upon them (if that long!) and yes, sometimes the wrong conclusions are reached and actions are performed that, after months of lengthy analysis by a crew of experts, are found to be less than ideal… but that in no way means that either malice or cowardice were involved. The pilot did not have the luxury of time or expert advice.
This is really the essence of air emergencies: You know something is terribly wrong, you don’t have all the relevant information but you have to make a decision RIGHT NOW - and if you guess wrong, you and other people might die.
So, to my mind, the question is not how did the situation appear to a tail gunner in another airplane, but how it appeared to the pilot of the airplane going down. What information did he have to work with? And how did he act on that information?