I'm glad that muye's friend did what she did. Made it obvious that this girl was being watched over, but wasn't overt in exposing him before he could get away with it and ruin xiaoyu's work relationship.
@Phoenix_VII In every workplace I've been in it is wildly against policy, for exactly this reason. You can't ever separate out the power dynamic from the relationship. If they're peers it's one thing, but as a direct report like that, 100% not OK.