Not only will you not die, you’ll have a great time. I went on my long travel 29er trail bike and it was fine. Had a few punctures so either run tubeless or higher pressures, and bust a spoke, but I have a burly wheel set so just carried on and the wheel was fine…didn’t even go out of true. I ran every run except for the double diamond one and to my surprise wasn’t the slowest out on the course that day.
It is knackering though. I ended up bailing about an hour or so before the session ended as I was just exhausted and didn’t want to have an off from being too tired.