i went to vault 81 to try and buy the overseers guardian and went into the depot and found alexis combes on the floor dead. is there any way to still get this gun without her? im playing this on the ps4

No, if she's dead, you can no longer get it. Why is she dead? Did you kill her? I don't remember any enemies in the vault.

no idea why shes dead. i did the molerat mission and left before i gave the cure to austin and havent been back in a long time. so i dont know what happened. that really svcks i wanted to buy that gun so bad

That's odd. I'd try reloading an earlier save and see if she's alive. That's the only way to get the Overseer's Guardian. You can get a Two Shot Combat Rifle in a random legendary drop though, and there's absolutely no difference between it and the Overseer's Guardian aside from the name.

Well on second thought if he left the kid sick the disease would have spread right?

You left the kid in a coma... ?

(sigh)