1) Show me in that clip the glider please. Oh wait, you can't because it's too small of a quality.
2) Show me his face please. Oh wait, you can't because it's too small of a quality.
3) Why would he throw a pumpkin bomb at Harry of all people? The symbioate is obviously messing with his mind. Maybe the guy who he throws it at is the mugger from the first movie, and he gets info from him (LOL SANDMAN ACTUALLY KILLED YOUR UNCLE NOT ME LOL) then says "I've no use for you anymore" and just kills him.