Apart from the things already mentioned, the rules state that "each hero who participated in the combat gains 4 experience points". If you follow this rule, also heroes who get knocked out would gain experience, which sounds really strange.
My interpretation of that is that they wanted to specify that you get 4 XP even though you never hit the bad guy even once. If you survive, you're good.
Yes, I say "if you survive" because I think that the "no reward if knocked out" principle supercedes the rule point above. But I could be wrong.