What was supposed to happen at the Battle of Bunker Hill?

I did the Battle of Bunker Hill last night. There will be some spoilers ahead regarding this battle and the story leading up to it.

Even after reading the wiki article on this quest, I'm a bit confused.

I already felt like something was going wrong with my faction associations, as Sturges never analyzed the data I brought back from the Institute, and I no longer had the option to tell Father "No" after looking around the facility and finding ample evidence of casual evil, but instead had to accept a quest: Synth Retention.

After getting the Battle of Bunker Hill quest, I immediately went to inform the Railroad, but they wouldn't let me tell them anything because they wanted me to work for them instead of the Minutemen. Eventually I just gave up and said I'd side with the Railroad so I could inform them about the attack.

I then went to Bunker Hill, expecting to escort the courser inside where we would ambush and kill him, as well as my escort. There didn't appear to be an escort. As the courser and I were walking toward town, the Brotherhood showed up in their flying death ships. The courser decided he needed to fight them instead of go inside, so I just shrugged my shoulders and killed him there. There were still synths everywhere, and I knew I was supposed to kill all the Institute attackers, per Desdemona, so I started killing them. They didn't shoot back.

In fact, there were four factions fighting, and none of them were trying to kill me. The Brotherhood, Institute, Railroad, and Bunker Hill all had soldiers killing the other factions, but nobody would shoot at me even if I shot at them. All the synths just let me shoot them in the back. When I got inside to check on the escaped synths, the Railroad and Brotherhood ignored me, but the turrets attacked me.

Were the factions supposed to ignore me like that? Did I do something wrong or unexpected?

Solution 1:

The Battle of Bunker Hill is a quest that is given to you by the Institute, which is why they weren't interested in being warned - it was their mission.

The reason you're allowed to inform other sides is because you'll always get this mission regardless of faction allegiance however if you're working for the Railroad they'll want informing because the synths you've been sent to kill by the SRB are in the process of being "saved"/smuggled out of the Commonwealth by the Railroad.

If you're aligned with the Brotherhood of Steel and warn them, then they'll request that you kill the synths.

At this point in the game it is possible to still be on friendly terms with every faction, if this is the case you can turn up to this mission and walk through multiple opposing factions trying to kill each other, with all of them acknowledging you as on their side.

Solution 2:

The generic answers as to how the battle plays out on sites such as IGN are all copied and pasted from each other's (other funded gaming sites) material which is also copied from WIKI's contributed by real players. Not one of them actually put in the time to explore every option as true gamers would have.

It IS possible despite what other people say (based on what they got from google) to have 3 factions alive. In order to do this you must exhaust all possible quests in all 3 major factions excluding The Institute. When the battle of Bunker hill quest commences inform only The Railroad. When you arrive at Bunker Hill talk to the courser and just kill him on the spot after the charge commences.

Enter Bunker Hill and you will note you are still friendly with all sides like your original post indicated. As far as they are concerned you are working for each of them so it is intentional they ignore you. Upon killing the Courser you should trigger the "visit father at CIT" prompt so you don't actually need to release the synths. This happens automatically. Return to Father at the CIT ruins (this is important) and tell him THE TRUTH about what you did. Do not lie or he will still consider you a friend and allow you to finish the railroad plan to release the Synths. (which gives you the railroad ending)

Telling him the truth immediately makes The Institute an enemy starting the Castle defence quests and scrapping The final Institute quests. This also stops The Railroads chances at releasing the 13 synths and stops that ending. Return to The Railroad and inform them you saved the Synths in Bunker hill but are no longer a friend to the Institute and thus no longer can help co-ordinate the synth escape.

This automatically chooses The Minute Men as your final ending. You complete The Minute Men questline by infiltrating the Institute and destroying it from the inside. You will get the Minute man ending and 3 factions will remain alive. The Brotherhood of Steel members will remark they didn't know The Minute Men were capable of such feats. If at any time you become enemies with the Brotherhood of Steel by killing one of their members that launches the final phase that you avoided in making these choices.

In which case as an enemy of The Brotherhood of Steel if you walk near Preston he will say "I think it is about time we sort out The Brotherhood situation". (the situation being that you are now enemies by choice) This will now launch the second phase of the Castle defence quest. If you have enough cannons placed on settlements inform Preston you are ready. He will direct you to the radio announcer who will co-ordinate a cannon strike on the Prydwen.

A really epic battle ensues as the Brotherhood shows up from every surviving base location in airships and challenges your Castle. Which in my case had over 700 defence with heavy lasers and rockets so it nearly crashed my system with the epicness. lol For extra lols leave a suit of empty power armor around and Ronnie should just help herself to it and run off massacring the enemy.