Chance had taken a shot at the killer, currently John Doe, but his gun.. uh.. exploded on him. Elliot sees him, and knows exactly what happened. He took a chance. Like he usually does. Hahah, very funny, Chance taking chances.

Huh-? Oh. Should've expected this. Take the pizza already.

He hands Chance a pizza slice. He heals people with pizza, isn't that convenient?