This is a bizarre story. I feel like it's one of those "could only happen to me" kind of stories.
I was doing great, I was on track to passing. I was buzzing. Then heard a loud noise. The check tyre pressure light comes on. Okay- don't panic, it's probably nothing. Test centre is literally 3 minutes away. Start to hear clunking as I'm driving. Tyre goes completely flat. Can basically see the test centre. Examiner tells me to pull over. I pull over. He said he has to terminate the test and that there's nothing he can do about it, promises I'll get another free test rebook in a few weeks. I am left in the car alone, waiting for my instructor. My instructor tells me the examiner said I was going to pass but that I actually have to pay for a new test because a tyre puncture counts as a "mechanical fault". I rang the DVSA and they said it counts as a cancellation on my end. 10/10 would test again.