Sloth
He could see how it was going to end. He was going to tell her, caution her to be careful. But she'd stopped and talked to that guy. That annoyed him but he was still going to tell her. And then she caught his eye and gave him something between a scowl and a smirk. She finished it by rolling her eyes and then turning away.
Then he knew, he'd say nothing.
She turned on her heel and took three steps before it happened. She slipped on the unseen puddle and came crashing down.
He smirked, turned and walked away.