1 - On Piotr as he holds a gun similar to Winston's, drawn and aimed in Simon's direction.
2 - On Simon's face. His eyes are tightly shut. He grimaces. Perhaps he turns his head slightly, as if turning away could help. Maybe even a tear streaming down his face if that isn't too much.
3 - On Piotr's gun, the trigger being pulled.
4 - On Simon. He flinches like crazy, putting up his arms in a useless act of self-defense.
LETTERING NOTE: I'd love it if there could be a big BLAM! covering pretty much the whole panel, with Simon standing in front of it, to illustrate the sound, violence, and so forth of the gun shot.
Onto page 28.
Start from the beginning.