As said top half to disable sensors bottom anti-tilt sensor.
How did you lock your car before testing the sensor? if you use the switch on the door the alarm wont arm, I have set mine off before when sat in the back and I locked the doors using the remote. I believe the switch only deactivates for the next time the car is alarmed and will default back to ultrasonics on, same with tilt. The time I set the alarm off it was a good 5-10 minutes before the alarm triggered so it may have a timer before the sensor is triggered.