The "..." at the end made it seem like he didn't really expect the guy to blow up into a grotesque monstrosity, but also have seen things go wrong too often. That's not what I think actually happened, but I would find it funny if that were the case. Like "Oh oops. I just wanted to give you some performance enhancing drugs. Maybe I should slowly walk away. If I ignore it, then it's like nothing happened."
Now I kind of want to read about a guy that's trying to be just a little bit bad, but everything he does always ends up being amplified to the point of being disastrously horrible. Because of his accidents, even when trying to right things, he becomes a super villain, but he really didn't mean to be one and keeps trying not to be one but wants to survive.
tldr; I'm crazy