PUGB Method of lobby/Ingame trickary

Does anyone know how PUBG do their lobby/game transfer? I can see it hits a loading screen joining the lobby and then instant transfer to the plane for all players. To me this seems like the lobby is in the same level as the main game (possibly sub levels loading while the timer goes down?)
I have made a lobby level and an ingame level and I get instant transfer to the lobby then when the countdown is 0 I hit loading times to the main game.
Any ideas? would it be acceptable making the “lobby” section far away from the landscape and then teleport players to the landscape after the countdown for quick spawning from the lobby?

Yep this is what they do. First load is lobby/character screen . Then when matchmaking finds match all players are second loaded into the game onto “spawn island” after timer finishes players are moved to the plane and game begins .

You can actually get back to the spawn island in game using a boat .

see map attached