I had a similar scenario. Nuketown HQ as well, the HQ was in the garage in front of the A flag side. All of the sudden I die from behind. The guy I just killed spawned directly behind me in the garden and sprayed me through the wall. Best part is, I respawn in the garden and shoot the guy who just killed me right in the back.
Spawns are awful on NT in general, but they're by far the worst in that game mode