For context: Since I saw a little bit of good in each of the factions, I tried my best to maintain good standing with each of them.
When I went to Bunker Hill, I was fully expecting to just meet the courser and kill him and his synths and be done with it. I WASN'T EXPECTING A FULL SCALE MASSACRE. I watched The Brotherhood (even if I didn't tell them about Bunker Hill), The Railroad, The Institute, and Bunker Hill civilians slaughter each other.
I watched Railroad agents (people I trusted the most in that battle) slaughter caravan guards and civilians. I watched Brotherhood soldiers (people I called my brothers) shoot and die at the hands of Railroad heavies as well. The craziest thing was nobody saw me as an enemy, so I just straight up walked up to each and every one of them and shoot them in the head. When I felt bad for a Railroad heavy, I shot a synth or a BoS soldier. When I felt bad for a BoS soldier, I shot a railroad heavy. When they finally turned on the civilians, I killed all of them. But I was too late.
When I went inside the Bunkerhill safehouse, I watched the Railroad and BoS kill each other, and I didn't try to stop it anymore.
Looted lots of cool Gauss rifles though.