Funny story. I think the worst way I've been woken up is by fire alarm, but it was the events after the alarm itself that made it so bad. I live in the UK and am from England, but go to a University in Wales. I'm not a Welsh speaker at all. Anyway, this happened just after Christmas in my first year. Most first year students live in and are allocated to University-provided Halls of Residence, and would have a 'random' firedrill per semester. The one that hit me was at four in the morning sometime in January.
The alarm itself scared the poop out of me, but I mentioned the fact I go to University in Wales for a reason. The fire alarm blared for a little while, but it was followed by an automated voice immediately afterwards. It spoke in Welsh. As an English speaker with no ear for Welsh - I find it very hard to understand the separate words in each clause, it was actually very scary being woken up by a very loud alarm, illuminated red walls, and a electionic Welsh lady ordering me to leave the building. Of course there was an English translation afterwards, but the shock had left at that point.
The icing on the cake was that my room's light wasn't working at the time and I couldn't find my boots. I only found a boot. I had to abandon the search for the other one because we were being rushed out of the building. I hopped my way to the meeting point for a little while, but it was uphill and I soon gave up. I figured a muddy sock was worth it.
And the little cute marzipan designs on top of the cake? I found my missing boot later, behind my room's door.
Yeah my hallmates didn't let me live that one down. At least I managed to get pants on!