Well, yeah. Everyone turned back when everything stopped...

[Then, he realizes that everything stopped being attacked by plants was probably linked to Archie's death. He swallows, and becomes more somber.]

When Archie died. Right?

[After a pause, thinking about how Archie had to have died, considering everything, he adds,]

I'm guessing it was someone just trying to defend themselves, right? There was no other way?

[Because now that the fact that Archie was dead is starting to sink in more, he's starting to notice a sinking feeling in his stomach.]