While training at the divisional headquarters of the Pesanga Brigade of Rifles in seventeen B.E., Shim volunteered with five other PesangaGears to go on a mission to reinforce Anvil Gate, which was under siege. After being given supplies for the mission, Shim and the others got in a helicopter, and were flown north of the fort, and dropped off to make their way to it under the cover of night. On the way, they heard somebody moving amongst the rocks in front of them, and took cover as whoever it was got closer. It turned out to be a Gear from the fort, Pvt.Padrick Salton, who had been sent out to escort them in. Shim and the others followed him back to the fort, where they met with Lt.Victor Hoffman, the forts CO. Pvt.Bai Tak introduced Shim and the others, and they then settled into their quarters. They then went to the briefing room, where Sgt.Samuel Byrne showed them maps of the area, and they made notes on certain areas for future patrols.
As the siege went on, Shah and the others would go out on patrol every night, getting at least one kill each patrol. They also hunted down goats and brought them back to supplement the forts food supply. During the battle to break the siege, Shim chased a group of Indie soldiers into a warehouse with Bai and Rifleman Cho Ligan. They killed twenty Indie soldiers in close combat with their machetes, and then regrouped with the other Gears in the tunnels below the city.