Having a neck grab on someone causes them to be hit by projectiles first instead of you.

If however the bullet misses or passes through the person being grabbed then it continues on and may still hit the person doing the grabbing.

code/modules/projectiles/projectile.dm

@@ -194,6 +194,13 @@
 	if(ismob(A))
 		var/mob/M = A
 		if(istype(A, /mob/living))
+			//if they have a neck grab on someone, that person gets hit instead
+			for(var/obj/item/weapon/grab/G in list(M.l_hand, M.r_hand))
+				if(G.state >= GRAB_NECK)
+					//If Bump() returns 0 (missed them or went through them) then we continue on to attack M.
+					if(Bump(G.affecting))
+						return
+			
 			passthrough = !attack_mob(M, distance)
 		else
 			passthrough = 1 //so ghosts don't stop bullets