Sounds like you’re trying to defend the indefensible....
He is. He’s got this entire scenario made up, where Scott is going to run into a crowded public place, shoot people with his non existent gun and carjack a car. So of course Scott HAD to kill him first! And Scott went back to pick up sunglasses, which were in a big block shape, and drop them by the dead man, just in case he needed them, ya know.