He only had a Secret clearance, not a Top Secret clearance. There is a significant difference in levels of access. A Secret clearance runs about $500 and does a very basic background check to verify you're not a wanted criminal and basic things like that. It doesn't take very long to get that and is generally something a lot of people receive when doing basic jobs where they might see something that is FRD, or Formerly Restricted Data.
To 'quit' my job with my top secret clearance, it took approximately 12 hours of my time. It isn't like a private sector company where someone quits and you disable their access. Oh no, there is a lot of paperwork that needs filled out, hand written signatures or emails to be retrieved, organized, and then submitted for approval for termination. Once approved, the accounts are scheduled to be disabled. I started my process 3 weeks prior to termination. After about 12 hours of my time getting information together, they submitted the paperwork. My accounts were scheduled to be disabled at 5pm end of day, but I'm told it took over a week before it actually happened. They were marked for disabling but the job didn't run for a week.
Digging further, he received an honorable discharge.
The guard gate wasn't anything impressive, other than something to show a badge. It said he showed a badge. Was it a visitor badge or his own badge? My experience the visitor badge is something very basic that says VISITOR on it with a number. Or he could have simply said he was a visitor and needed to get a badge inside. The guards generally aren't paying attention especially with the hectic morning rush of people coming in. I've been through those gates hundreds of times and know it wouldn't be hard to get through one of those basic gates. If it was a Top Secret place he was trying to access, no way in hell would he have made it through.. but these were just basic workers that weren't going into sensitive areas.