When attempted to grab the chest, it gave me a 5hp life capsule. This life capsule does not seem to have a correct <END placement, as it keeps going to event #0500 where it just does a different script. Could be game breaking in some cases.
Ah, right. I'm guessing that most of the Missile chests rely on the global missile event to call <END. I'll have to insert one manually whenever I'm replacing a missile chest event with something else.