Another rationalization for a deathtrap is when a particular villain simply enjoys leaving his victims some small chance of survival, just for the sake of sport.
It would study a superhuman, often by forcing them to run through some sort of deathtrap scenario, then used the collected data to create duplicates of the superhuman being.
He seems to possess the powers of his previous incarnations, escaping a deathtrap by devouring an entire silo full of grain.
Terror returned to rescue them from a watery deathtrap.
On some occasions, the deathtrap is a machine that absorbs the energy from the hero/heroes.
This even goes as far as heroes, or other villains, insulting a villain for attempting to avoid using a deathtrap or staying to watch.
Its ecology can be politely described as a layered deathtrap, the planet's surface being encompassed in shadow by wroshyr trees that are many miles high.
It is a deathtrap, anyway.
