Mist layer 15 bug

At levels 11 and 12 of the fog, open a portal and enter levels 13-15. When brushing monsters, press ESC to return to the character selection. After entering the game, you will reach the 11th and 12th levels. Remote skills can be used to block the monsters behind the door and output them. Finally, use Flash to jump to the 13-15 level area and kill the boss to complete the challenge.
With this method, there is basically no damage and you can challenge the fog layer 15。
You can use flashing and try several times. You can freely shuttle back and forth from the entrance of floors 13-15 to floors 11-12.