Doctor Strange trains a reality manipulator to control her powers once a week so she doesnīt accidentally causes a catastrophe so yes, it can be done. The problem is that it depends on the story, the writer either wants to write this character as: nothing can be done he/she must be killed or as he/she just needs more training. Bendis did the first with Wanda and Mathew Malloy while Thomson did the second in her Jessica Jones series. But if the argument is about, itīs fair to kill a person just because of what they could do, I would say no, neither itīs that heroic action, imo.