I'm concerned that the secret service agents were hassled by the Chileans and even momentarily prevented from protecting him. This is NOT GOOD.
I think this is all due to a communication breakdown. Somebody, either the SS or Chilean security, failed to tell the guard at the door that the SS agent would be accompanying the president inside the building. No matter where the failure occurred, the SS is probably undergoing a serious grilling at this very moment, since they're the ones ultimately responsible for the president's safety.