If something comes up during the background check, the sentries might be under orders to detain the individual for civilian law enforcement. I’ve stood armed watches before, but not at a base gate so I don’t know what information comes up during the background. It’s more common for sentries to just tell the driver to…

I’m from Texas, but I’ve never been around Fort Hood. I’ll have to take your word there. I’m only familiar with the east coast Navy bases.

Yeah, it’s called the UCMJ and they will slam you with it the moment you mess up, especially while standing an armed watch.

Just so you’re aware, the base’s commanding officer probably wasn’t even involved in the arrest. The chief of the guard was probably called (probably an enlisted soldier, e-5 or e-6) by the sentry, and they followed orders as directed. I do think it’s weird that the driver had apparently delivered to the base before…