Why is the X-ray machine hand switch divided into two gears

Why is the X-ray hand switch divided into 2 gears? It is to prevent the doctor or patient from accidentally triggering the exposure button. The current X-ray hand switches are basically 2 gears, 1 gear for pre-exposure, and 2 gears for exposure.
Briefly introduce our X-ray machine hand switch:
Model: L01 (X-ray hand brake switch, hand brake switch, exposure hand brake, hand brake)
Overview: The first step is to control the exposure preparation state, and the second step is to control the exposure.
Parameters:
Mechanical parameters: handle size: length: 10.5cm width: 3cm
Hand brake wire length: 4 cores 3 meters (wire can be customized)
Gear position: 2 gears
Electrical parameters: switch life ≤ 400,000 times
Working voltage: AC: 125V 15A
DC: 125V 0.6A
Material: (1) Matte surface
(2) Smooth surface
5. Advantages: (1) The design of the internal double knob and double micro switch.
(2) Design of spring bar trigger
(3) The button switch is a flat step