four wall treatment

Analogous to a 'tune up.' Typically performed one-on-one, behind closed doors, in a private office/room.

Recruit #1: "How the hell did Jones break his beak like that? Is it true that he got the four wall treatment from Rodriguez?"
Recruit #2: "Shit, brah, all I know is that he was gettin' an ass chewin' from Gunny Rodriguez, then I heard him mouth off with something, then it was like 'BAM, BAM, BAM, BAM.' Then the shit got real quiet. So I took off before Gunny four-walled my skinny ass next!"