I find it odd that a military airbase isn't aware of the traffic making an approach to land there
If you look at the photograph above you may note the close proximity of the airbase and the airport. Therefore, the airbase tower must be quite used to seeing inbound traffic to the civil airport. If, as in this case, an aircraft makes a sudden approach to their own runway I would imagine there's not much one can do in the very short time involved. Don't forget that the aircraft will not be on the airbase frequency. Best they MIGHT be able to do is ensure their runway is clear and then just watch the aircraft land.