Tony had relied on the Arc Reactor to keep him alive since ... without the need for the Arc Reactor to remain a part of him. Pepper Potts recovers from the effects of Extremis Aldrich Killian ...

The closing scene of Iron Man 3 features Tony disposing of the most recent Arc Reactor, throwing it off ... the most of that ...

Whether it's Iron Man fiddling with his arc reactor or Star-Lord getting hosed down, you can almost always count on the hero of any given Marvel movie to lose his shirt -- it's practically a trope.