What would an examiner do?

I called at the test centre and asked an examiner this question when the fire extinguisher in the rear footwell got punctured at the start of a driving lesson (could have been a test).

You can see the resulting mess.  Interestingly, he STILL replied in the usual way: "I'd have to be there to say what I'd do".

Fair enough; it could become a matter of test timing rather than test safety.  (The dust had settled after two minutes with the windows open).

The video on this page illustrates a multi-car scenario but poses the same question ...