Betrayal at House on the Hill: Haunt 2: The Séance
For the heroes, there are two ways to win:


  they either defeat the ghost after the traitor takes control of it, or they burry the ghost's bones after they summon it.


They have 5 turns to find and bury the bones. The track marker advances after the players turn. If that hero is dead but other hero's are alive, you just advance the marker at the time the dead hero should have had his or her turn.

So no the heroes only lose if the last one of them died.