First off: before you say Holy CPR, Batman! It was a snog. That is like no mouth to mouth we've ever seen. Also, she wasn't drowned, he punched her in the face. There are no chest compressions and we do not see Batman clearing her airways. At best you could suggest there's a bit of ambiguity – a 'did he/didn't he' kiss her.
And he totally did.
But why?