He is easily annoyed and very sarcastic, especially when dealing with people lacking a normal Intelligence. Unless you approach the gate with proper authorization, he won't permit your entrance into Navarro under any circumstances.
If you get escorted off the base, you will have to talk your way through the gate guard to get back on base. If you can't persuade him you are a soldier in the Enclave, the base will go on alert and everyone will initiate combat.
He does not allow you onto the base if you have any companions in your party.