Dave would find the building to be a lot tougher that it looked, and after a few seconds of pounding at the gate, he was listed and pushed back by some invisible force.
The source of the footsteps eventually came into the light, revealing two metallic feet, walking around on their own quite happily. "Good luck with that, but if you do kill me, I have no hard feelings. That's how the world works after all." The voice echoed around the plaza, pinning down its exact location would be difficult at best.
X-9 would see an awning he could stand under above the door.