MP5s are modern high-quality weapons. They'd need MP5s in case a group of terrorists attacked the checkpoint, or got caught going through the checkpoint and de

MP5s are modern high-quality weapons. They'd need MP5s in case a group of terrorists attacked the checkpoint, or got caught going through the checkpoint and decided on plan B (just kill as many people in the airport as possible). They need security clearances to ensure that they're not going to help someone get a bomb onto the plane.