slinging in his room and  catches the lamp to pull it towards him, it doesnt appear to move  very fast off the chest and looks more likely to fall on the floor  before the shot changes. When it cuts to Peter, it speeds past his  shoulder a lot faster to smash on the wall behind him. Furthermore,  Aunt May would have easily seen the amount of webbing all over the  room through the gap in the door as shes talking to him.