Last night we had a situation where a sorcerer was being forced to enter the dread sarcophagus that would resurrect an ancient evil. It wouldn’t resurrect the evil for just anyone, the character’s ancestry mattered. The sarcophagus was protected from sorcery with four sorcery/sorcerer killing stones, one touch of the stone and the sorcerer would die.
The player knowing that his ancestry was the missing ingredient to the baddies’ plan decided to launch himself at the sorcery killing stone to kill himself.
Unfortunately his sister was on the battlefield outside and when the battle was lost she was captured and lined up to enter the dread sarcophagus herself. Thus the player character’s sacrifice merely averted the apocalypse by a few days making his death much less significant.
Thinking about the character’s options maybe he could have made one last roll to see if he could have got a garbled transmission that could have impacted the situation. But alas it all ended in tragedy.