Well, I know you are supposed to be prepared for a flat, but I never am and truth be told I rarely get a flat. On my ride yesterday, I got one. I have not pulled it apart to look at what happened but it doesn’t really matter. I was in the middle of the woods, 5 miles into an out and back when it happened.
The first thing you need to decide is whether you are going to walk or ride. Walkings a pain but it’s a sure way to minimize any damage. Riding will destroy your chance of saving the tube and will likely mean a new tire so think it through.
If you decide to try riding here’s what you need to know: If your suspension is easily adjustable - soften it up. Try to keep most of your weight nearest the inflated tire. Mine was on the rear so I slid forward as much as I comfortably could. Next go to a low gear, keep it around 5 mph for the least risk. Don’t ride over obstacles and loose stuff. Get off and walk over them. Take both the uphills and down hills slow. The flat tire will wiggle around just like riding in sand, just keep it slow and easy and you should be able to ride out.
If the tire comes off stop! No sense in destroying the wheel as well. Only do this on dirt, pavement will destroy the rim. If you need brakes you are going to fast.