This just isn't true. They felt exactly the same as OP up until the moment they died. A sudden death is, by definition, something that can not be regretted.

You seem to be assuming the mindset that nothing matters after an individual dies.

I'm sure you are not surprised to hear that many disagree with this.

To that specific individual, it doesn't because they are dead.

As for what happens in the realm of death, we'll see when we get there.

> To that specific individual, it doesn't because they are dead.

I wasn't clear enough. The decisions one makes during their life are affected by whether or not they care about anything that happens after they are dead (any many specifics beyond that). Many people do things whose primary impact won't be felt until long after they are gone. So it isn't true to simply say that nothing matters after the individual is dead.

I'm sure some of them felt some amount of regret in the last, terrifying moments between when they realized that they were going to die and when they finally lost consciousness.

Who said "sudden"?

The vast, vast majority of people who go to those places don’t die.