The switch for one of the plates of my cooker has come off?

Therfore the plate is always on. (It is an electric cooker)
It has to be switched off from the mains.

The cooker is built into the work top.
I need to take the top metal covering off to see how I can get the switch back in.
But to do this I have to take the other 3 switches off.
I'm afraid to do this in case these switches won't go back in.

Any advice?