This is an extension rule (^Ex) and is not part of the official rules.

When a character is killed, though they are mechanically dead, they may save vs. death once, any time up to and including the 1 turn downtime at the end of the encounter. If they pass, they may speak for up to 1 minute. After that, they are gone.

No spellcasting, device use, ability use, movement, combat, or anything other than speaking is possible.