Still not sure the story is ‘straight’.
Local news says “Two men in a stolen car apparently drove toward the base about midnight and tried to go through a gate at Northern Avenue and Litchfield Road.” That location is way north of where they were stopped.
Perhaps they DID bust the gate at Lightning and Litchfield, drove south on the base, and then turned east on the overpass where they got capped?!??? dunno.
Your scenario matches what was said on a Fox News live link about 4 or 5 hours ago...
The ‘security check point’ where they failed to stop was actually a military cop in a pick-up truck; i.e., a roadblock.
Again, according to commentary on the live link.