Try for the door, this will trigger dialog with sergeant. Ask him what is behind and what is he doing and this will lead to dice roll and if you win he'll let you in
Interesting, does Charisma score modify that? My main is a Rogue and I am level 3 but I am indecisive about where to go with sill points (other than the obvious). I want to explore dialogue and other non-combat options so is there any feedback you can give on Charisma being worthwhile in this regard? Maybe a point or two?
Thanks!