Bishop and his team were sent from the Citadel to Chesterbrook after a scribe found a reference to a storage box of mini nukes, along with the key, at Chesterbrook. Alongside Paladin Northup, he and his team were ambushed by super mutants after retrieving the key for the container. They were constantly attacked by mutants every several hours, resulting in them going without sleep for several days. They became engaged in a knowingly suicidal losing battle. If the Lone Wanderer showed up, Bishop would have warned them about the situation and advised them to leave the area while the mutants were still focused on Bishop and his team. If the Lone Wanderer offered their help, he would have requested they exterminate any super mutants they stumbled across in the nearby area. However, he had literally nothing to offer them, except him and his team's sincere thanks.
↑Bishop's dialogue: "We were looking for Fat Man ammo. One of the Scribes found a reference to a storage box in some old documents. We found the box, alright. And the key. But then the Mutants showed up. If I didn't know better, I'd swear that this was a trap!"
↑"What does it look like? We're fighting a losing battle! That's what's happening. They just keep coming. We haven't slept in days. Every couple of hours, more show up."
↑"I suggest that you head out of here while the Muties are focused on us."
↑"The best thing you can do is eliminate any Mutants you find. I have no reward to offer you but my thanks."