Your characters all are in the entrance hallway to begin with. They are standing in the hallway near the double doors, with no recollection of anything after the flash of light and their subsequent disappearance. Indeed, they do not even remember standing up. They are all wearing and carrying whatever they were wearing or carrying at the time of the event.
You guys can all continue the story on the 1.1: Entrance page by editing it. You can post your characters thoughts, words and actions. Keep writing in the third person, but it is now in the present tense.
As this is all still experimental, I expect there to be some bugs. I may have to edit for logic or continuity's sake. I will also edit it whenever a character interacts with the environment. As well, you can examine something in detail and I will provide further description. When you enter another room, another page will be created for that room. If changes to this system are required, I will make them.
Umm, other things. Try not to post too much too fast, without giving the other characters a chance to react. I hope conversations don't flow too slowly, but you don't need write much in your updates, so presumably it will be fast enough. Have fun.
Okay, new things: kind of the opposite problem I anticipated, but I suppose it's a good problem to have. I'm going to have to limit the posts to one per person per day, as it's going too fast for some people to follow, including me.
Retroactive posting: if you want to do something before someone else does something you can post it before the other post, as long as it doesn't affect the already established future. In the same vein- you can also interrupt someone by cutting off their speach and deleating what they said after if your character would do that. Long speaches with eleven people in a room feel somewhat unrealistic, so try not to make them unbelivably long-winded.
Also, if you really must change something you wrote previously you can, again, as long as it doesn't affect the already-established future.
Some people have been adding a few little setting description details in their posts. This is cool as long as it doesn't contradict what I've already established. If your detail is not consistent with what I have in mind I'll just delete it, no worries.
Chapter 1.3 takes place in multiple rooms, so to make it easier for me I split it up into pages based on rooms. Your character starts Chapter 1.3 in the room e was in at the end of 1.2, obviously, so only post on the corresponding page. If you go into another room, post on that page. This is all pretty self-evident, I think, but best to clarify it from the beginning.
As well, I think everyone already does this, but I'm going to make it official. Separate posts by different people with a series of underscores like this.