They could have had a bunch of extras walking around and then going into a panic, but for what purpose?
Realism?
"That's what he said, yes, but it's clearly not what he meant. He'd stop Peter by killing him, but he'd still be the bad guy (no one else was around). All the other heroes would still want him dead, so he wouldn't really be a hero."
Well, I didn't necessarily mean that he would be a "good guy", simply that he was taking odd satisfaction in the belief that he wouldn't be the one who caused all the deaths.
Regardless, this episode was several cuts below the quality I have to come expect from the show.