On the one hand, games should enable you to tell the story you want to tell. If you're fighting against the games rules and contents to make your story work, changing a rule, or even the system you're using, is the right call.
On the other hand, we've all seen stories where the established rules of the world break for a moment to let the protagonist win a fight they'd obviously lose. It's always a low point in the story, unless the story is just bad. The audience starts to feel like there are no stakes because physics will just bend to help the hero win.
If the rules of the system already in use would kill a character, then maybe the story is one where that character dies. It's not the one you planned, but it's the one that's happening.