Shortly after the Grosvenor House Hotel incident, a zombie armed with a knife chased after the Rogans and prepared to G whilst riding in a car. Stewart noticed the problem from a rooftop, but waited until the zombie was right on top of G. He then managed to obliterate the zombie with a shotgun, remarkable considering the distance. Stewart suggested that this wasn't the time he had rescued G and declared he was charging for the ammunition next time.
Later on, Gary accompanied his AMS friends to the Isle of Dogs to storm the Fear Foundry. His situation grew dire when, only armed with three bags of explosives, he was surrounded by a number of mud monsters from the river. With advice from G, Stewart aimed for the zombies' heads and fought his way into One Canada Square. After Lisa Rogan defeated their opponents with more explosives, Gary helped his colleagues finish off the last of the zombies before hearing that the Resurrection Men had helped to finish the job.