Should I be worried? I'm going to assume not, since I've not been named-policed yet. It would be nice for someone who actually speaks Hebrew to give me an opinion, because there is a wide spectrum of "wickedness" all the way from putting practical jokes to trying to destroy the world and I know that translations of words always miss the subtlies and cultural associations.
Mostly I think that if you take the span of human language, including slang, there is likely no safe word to name your character that doesn't mean something bad to someone. Ressha's just annoyed because she's kind of sweet. She wants to be a tank because she's noble enough to step up and make sure other people don't get hurt. She doesn't have a wicked bone in her body.