1.We must have active elytra wings on singleplayer world (checked at flat [void]).
2.When flying, sharply turn up/down (left/right weren't check).
3.Here we go! One of multiplayer's crashes on singleplayer world! It also tooks half of heart bar (like hitting a wall)

It repeat about 3/4 times if we can escape this

To escape:
1.YOU MUST HAVE FIREWORKS IN INVENTORY
2.Start clicking Space bar and RMB quickly after enter the save and DON'T change your rotation