I think it is a shortening of "passed on", which implies transition without regard to success. But I agree it is ambiguous and I think we should start saying "escaped" instead.

"Aunie Rose--bless her heart!-- I just can't believe it's been three years since she escaped."

"The Jergenoid family is saddened at the recent escape of their Great-Uncle Abernathy Terwilliger Jergenoid, a man of great agility and distinction, who escaped last Friday at four-fifteen pm."

Yes, that would definitely shift the tenor of the conversation a tad.