If I saw nothing soft to hit, I would crash the medium as soon as possible. Maybe throw my weight to one side to make in fall over.
Stay on
Jump off
Try to steer it
Try to slow down by sticking your hands into the ground
Scream
Tell everyone to get out of the way
Crash into a telephone booth then call for help
Make sure someone got it on camera
Something else
If I saw nothing soft to hit, I would crash the medium as soon as possible. Maybe throw my weight to one side to make in fall over.