Wash's warning wasn't actually necessary - Jamie was familiar enough with grenades that as soon as Wash looked as though he was ready to throw it he brought his hands up to cover his ears, ducking off to the side behind where two sections of the corridor wall met up, a metal brace sticking out just enough to provide a tiny amount of cover.

Between that and Wash, the concussive force was more or less absorbed and he remained on his feet. This was good, because as soon as it subsided he was was off and running again, ignoring the bits of zombie that now were scattered throughout the hallway. The noise would draw more of them, but the mess that had been left behind should be enough for them to get to their destination.

It didn't stop him from calling back to Wash to make sure the man was following. "That'll take care of them. Come on!!"