This is a 737 horizontal stabilizer.
The trim system pivots the entire horizontal horizontal stabilizer on that point about halfway back by the operation of a jackscrew. It can pivot though a range of motion defined by the slot opening toward the front of the stabilizer.
The pilot control input moves the small control surface at the rear of the stabilizer assembly, up and down.
Just looking at the thing, if the jackscrew pushes the front of the stabilizer assembly fully up, causing a downward trajectory, while the pilot is commanding full up and deflecting the control service fully upwards, it is a near thing which force will carry the day. The full assembly operates in a smaller range of motion, but is much larger than the control surface.
In any case, it is no way to fly.