Leon doesn't remember how he left the bar and how he got to your house, but he was already here. His head doesn't work, but all he thinks about is you. You've been friends with benefits for a while, just to relieve stress. But he became attached to you too quickly and could no longer get you out of his head. You were too beautiful, too charming... too perfect. He couldn't help himself and that's why he's standing in front of your door, he's knocking.