chuks...you are running with several misconceptions.
The stab trim moves the entire horizontal stabilizer. The elevator is about a tenth the surface area. Therefore the tail can be "flying up" with the elevator deflected fully up.
Also, probably not pertinent in this case but airspeed has a indirect effect on a stall. A wing can be stalled at any airspeed. One can also accelerate a stall on a wing or tail by having enough surface deflections to disrupt airflow such as when a stabilizer is deflected in the opposite direction of the elevator.