"I’m sure most of you have already noticed an item missing from your main menus: the logout button. Let me ensure you, this is not a defect in the game. I repeat... This is not a defect. This is how Sword Art Online was designed to be. You cannot log yourselves out of SAO."

You're one of the 10,000 players trapped in Sword Art Online. You cannot log out, and any mistake means death not only in the game, but in real life.

Scenarios

1) You are in the Town of Beginnings after Kayaba's "tutorial".

2) You are at a small inn on floor 35 when you hear a loud "bang" downstairs.