"Oh, my God, I made a mistake, I made a mistake."

Last words that must be the last words of many people who die without leaving someone, as in this case, who can report them.

ADDED: This story had me remembering this article from 2003 in The New Yorker about people who jumped off the Golden Gate Bridge:
Survivors often regret their decision in midair, if not before. Ken Baldwin [said]...

"I instantly realized that everything in my life that I’d thought was unfixable was totally fixable—except for having just jumped."

Kevin Hines... recalls, "My first thought was What the hell did I just do? I don’t want to die."