I'm sorry, but how far would you go to try and save your dying daughter? It made perfect sense to me that he would try to kill Spidey since he was standing in his way and had already beaten him once.And if you didn't notice, the general public were pretty far back from that construction site. The only innocent life he was really risking as he would have seen it was MJ's. He wasn't a bad person though, just someone desperate to help his daughter and given the power to do it the only way he knew how, and although it was wrong, he realized it in the end.