When I first boarded the Prydwen and met with Elder Maxson I killed him for his coat
This made me an obvious enemy of the brotherhood of steel and cancelled every quest I had with them.

Anyways because of this I joined the institute, but when I talk to Allie to start the "Mass Fusion" quest my next objective tells me to 'Relay to mass fusion' but when I go to the marker nothing happens.
I read online that once you enter the room a pop-up message should display saying you'll be an enemy with the Brotherhood of steel if you continue, but since I'm already an enemy of theirs nothing happens and I don't think I can progress any further.

Anybody else having this problem or have any tips for me? I can't complete the institute quest line without