This week there was a bug introduced where sometimes that second main gate will not open. The way to bypass it is to go into the corner beside the door where the wall of the room meets the outer wall of the doorway and fly into that corner using space to glide without holding W, then keep spam inviting your group members to join on you, eventually one of them will spawn inside the doorway and you can bypass it. This also works on other doorways btw, and this is how some groups do speed clears to bypass early rooms for practicing dotm for timed runs.
Edit: also sometimes one of the people that you invite to join on you will make it kind of like half way through, where they are sticking into the wall. if you see that happen, have them start spam inviting as it will be easier for someone to make it through on them then it will on you since they are already halfway there.