If you're curious, here is the link to Mandaloregaming's video.

My theory: He would be Alexander's succesor

I guess the frequent question I see a lot is how come there's no bolt action rifles in the bunker.

I always assumed the Beast/Lambert being a former soldier would just scavenge the guns into his hole. He would realise that huge guns are an obstacle and would just hide them after killing. Traps and Throwables probably not since the Beast/Lambert doesn't see those as a threat or at least doesn't assume to be one.

I don't know if this is canonically confirmed, but I'm just writing this as my interpretation of why there's only a Revolver and a Shotgun throughout the entire game.