Read about it indeed you will, and see it eventually. This was a sneak peek at the true final level of the game, but with only parts available to explore - not including behind that door you were trying to rocket to, but good to keep that one in mind for the subtly different Aye Mak Sicur :).
Endless fun with respawning jugs! Oh and next time you see this portion of this level, you'll be in vacuum! But you'll be no stranger to that state soon ... all too soon.