I have not flown the 737 ...
But lets do what you say.
The system kicks in and trims the aircraft, lets say, 8 or 10 degrees Nose Down, before you react by acting on those 2 switches.
Now you have an aircraft trimmed 8 or 10 degrees Nose Down, and, to the best of my knowledge, you can not trim Nose Up because those switches are Off.
Do you think that you are going to get out of it ?