This happened during our mocks. We kept our bags to the side, and my phone was inside. I'd switched it off, but it switches on if there's an alarm set. I forgot to turn off the alarm, so it started ringing. Worst.Five.Minutes.Of.My.Life. At first, I wasn't sure if it was my phone, but then I realized it is as I put two and two together. The teachers took my bag out of the exam. Thankfully, they understood it was an honest mistake. Well, I always make sure my alarm is off now.