Update 11.10.2019
Valve just add non-build territory on place where i build teleporter on video. You still can get out of bounds using spell in other spots or if you get lucky and just walk through 1st wall
The video shows a technical way how to get on the skybox of map sd_doomsday_event, requires a random and skill
Can i do this on valve server?
-Yes, you can!
Minify exploit found by Ninja Cookie. Improved by me
Music in video Dance Dont Delay