You're missing her nuance entirely, though - Edit 1
Before modification by Tom at 09/05/2013 05:40:40 PM
The issue is that he did it with his bare hand. She wanted the spider dead, but because he did it with his hand, she's wondering if that hasn't somehow tainted his hand, made him sort of irrevocably dirty by contact with the spider, that sort of thing. At least, that's my reading of what she's saying.