Here's a total non-conspiracy guess:

Some guys from DC and/or Baltimore are stealing cars from the more affluent suburbs. So they steal the car and avoid major roads, like parkways and interstates, because those roads are heavily policed. Instead, they use the less trafficked (and less policed) state highways.

Problem is, they're from the city, and have zero knowledge of state highways. So they rely on the stolen car's GPS, which eventually leads them to Highway 175, aka, Annapolis Road, aka, the NSA's driveway. Here's a map.

I think these guys are unwittingly driving stolen cars right down Main Street of Coptown, USA.

This is reaaalllly reaching.

Maybe it's just something to "sprinkle" an agenda into regular news to Keep NSA relevant?

Oh look, gate crashers (in other words terrorists)! Those "terrorists" are trying to get to the NSA, therefore the NSA must be working! If terrorists hate them, the NSA must be good and all that is right with america.

This Thanksgiving, enjoy your apple pie, and don't surf in anonymity, you don't want the terrorists to win do you?

Either that or since it's only 2 times, it could be a coincidence. Maybe the NSA's drive is at a dead end, the fleeing vehicles were just trying to get away and didn't know the area.

2 points make a line, not a pattern.

It's the NSA. They don't know who, or what, might be in the car. If it's coming toward the base and refusing to comply, it might have an explosive in it. If it's leaving the base and refusing to comply, it might have sensitive information or equipment.

It's also important to point out that the NSA has it's own onsite law enforcement, and they work for the Department of Defense, not the Department of Justice. Different rules.

What has seemed right to you lately?

Testing remote-control exploits on vehicles perhaps?

The agents of the NSA are encouraged to rob vehicles to come in to work. It keeps their wits sharp and guarantees no bugging equipment was attached to the agent's vehicle LOL