Okay, um...
There's supposed to be some downtime on Yggdrasil right now since a lot of the characters in the restaurant district just got done with a fight scene. I really don't think appearing like that is conducive for any of the characters involved.
That being said, if you want to get on Yggdrasil, the multiversal void is breathable(you won't suffocate in it at least) and you could appear outside of it, and if that was the case people would probably move to help Guts get inside.
On top of some of the issues with the sudden mass death and destruction, it's very hard to teleport inside of Yggdrasil from outside of it. Again, the whole thing with the SE attack was meant to be strange and unusual.
Again, I don't mind if you want to get there but most of the players involved wanted some downtime after the fight, not to deal with huge amounts of destruction and death.