I have a new appreciation for the big leagues perk [spoiler]

So I’m playing my first survival run and my build is a stealth Melee character with 1 endurance, I’m a glass cannon. So I get to Kellogg, he has a skull next to his name and the room lights up so I know getting a sneak attack is gonna be a challenge but idk how else I’m gonna kill him. First attempt I talk to him and immediately run out of the room to hide. A synth comes looking for me and I kill it and go back to hiding. Next comes invisible Kellogg. I can’t target him in vats so he eventually gets close enough to spot me and one shots me with his pistol. I’m thinking I’m screwed how am I supposed to kill him?! Next attempt I just go balls out. I talk to him and before he goes invisible I queue upas many attacks with pickmans blade as I can. I manage a lot of hits because I have 9 agility but I still only manage to get him to half health before I get out of vats. I panic and run for cover! He’s on me though and while invisible is hitting me with his gun I presume but it’s not doing a lot of damage. So I slash at him and eventually the bleed damage starts racking up and I take him out. YAY! I loot his corpse and make my way out of the fort pyrdwen flys over and I start on my way back to DC. About halfway to town I decide to check out my new loot. Kellogg armor is awesome, took his cyborg parts ect, but his gun is missing? It wasn’t on his corpse! Suddenly I realize I must have disarmed him during my initial attack! That’s why he didn’t shoot me. The big leagues perk random disarm proc saved me. I can’t imagine how many times I’d have fight him or creative strategies I’d have to employ to kill him otherwise. I had to run back and search the room for the gun which was under the desk he walks out from when you enter the room.