A comedian was telling a story about a commercial flight that, due to pilot error, got within a hundred feet of the ocean before they recovered.
"Who wants to recover after that?" He gestured, using his hand in the classic 'flying plane' configuration to indicate a plane diving down to the ocean. "I slept with your sister!" then noses back up to the sky. "NO, I didn't!"

Movies are full of that near-death disclosure of a hidden fact or a long-held guilt on the conscience.

What kind of motive drives that sort of thing? I'm inches/seconds/heartbeats from death, and I don't want to carry this fact any more, i'll force you to deal with it? How's that for selfish? _I_ will go to the next life with a clean slate, you have four seconds to determine your feelings on this fact, not enough time to resolve it and punish me for it.

I gotta think I'm taking MY secrets to the grave. For one thing, if, for example, I had slept with my sister-in-law, and my nearly-telepathic wife somehow didn't notice it, she deserves better than to die while trying to process this fact at a time of maximum stress.

For another, of course, the movies are also full of near-death situations turning out to be a happy ending, or would be if not for the burden of the disclosure fucking up the celebration. "We lived oh shit!"
"Oh shit is right, bud. So, tell me more about _____."
I mean, it would be one thing if there is an afterlife, and if part of it involves full disclosure, I can see spending eternity discussing all our crimes against each other and maybe coming to a better understanding of the person I thought I knew, but if this life is all we have, I don't want to fear-response it into the shitcan for a near-death-scare.

Also, considering how I respond to stress, I'd be 20% likely to blurt out, "I slept with my sister," by mistake, which does diddly-squat for taking a weight off my shoulders. Especially if Marie is on the same plane...