Deathtrap behavior

A room with a deathtrap kills whoever enters, with some chance, on the spot -- no fight, no warning. Tread such places with the utmost care, and never drag a corpse or drop your gear where it may be lost forever. Anyone who senses traps -- through perception or detect trap -- stops on the threshold with a warning the first time; a second step right after it goes through. Without that sense, a wise character may still get a bad feeling and stop: the wiser, the likelier. Either way the stop also halts a path run.