Every time I see gifs of this scene in season 4
I keep thinking about this line from Stiles in season 2
"You see, death doesn’t happen to you. It happens to everyone around you, okay? To all the people left standing at your funeral, trying to figure out how they’re gonna live the rest of their lives now without you in it."
Because look at him. That’s what he’s thinking. Scott’s in trouble and there’s danger all around, but Stiles doesn’t move. Even when everyone else starts to run off, he doesn’t. He’s watching Derek with this terrible look on his face, because Derek is dying. He says he’s not, but Stiles sees it. And what is he going to do if he comes back from this rescue mission and finds out Derek is dead? How will he be able to go back to Beacon Hills, go back to school, go back to life if Derek is dead?
Scott is in terrible, unknown danger, and Stiles can’t even move until urged to go multiple times because “What am I going to do if Derek dies?”