Positive energy plane has major positive-dominant trait. Its positive effects are granting fast healing 5 ability and 5 temporary HP per round for fully healed heroes. On the other hand, failed DC 15 fortitude save causes hero to become blind for 10 rounds. What's more, if hero has those temporary HP, failed DC 20 fortitude save causes hero to spontaneously explode.
Can this mechanism be used in a trap?
For example, can I disguise the trap as pool of healing that heals heroes that have entered it (as usual), but if they stay too long they may explode as on positive energy plane?