but I'm guessing it was the screaming and being dragged away, as at the CDC?

No, but you are right, that did happen - that actually happens in lots of apocalyptic type movies, I'm sure it was in my subconscious.

Actually it was the moment between Rick and Shane that I am slightly obsessed with that I twisted and gave to Jon and Stephen...Stephen leaned forward, pressed their foreheads together, one hand coming up to thread through the hairs at the base of Jon’s neck..