False starts with a guard can be tricky. If the running game calls for the guard to pull a lot, you'll see that guard get more than his fair share of false starts, as the key to pulling successfully is moving quickly off the snap. You'll see a guard FS most frequently on first down, usually a running down. If you pay attention, you will see that when the guard does FS under those conditions, he'll be tending to move back and toward the center. Of course, I don't know Baltimore's scheme that well, so I can't speak to the "conditions" under which he got flagged.