Board Thread:Questions and Answers/@comment-2037710-20131220094434/@comment-5592165-20131220100108

Umm... start with a reference to a part of what I post on the main page:

Everyone then decided to proceed to Floor 76. Many irregular phenomenons happened one after another, such as earthquakes, the corruption of all skills and items data, etc. They also found out that the Teleport Gate could not bring them down to Floor 75 or any other lower floors anymore.

Then firstly, Yui pop out from Kirito's inventory... (Yes...just like that...)

Later they met Liz as well. I think she said she got worried and teleported up to Arksophia, same goes for Silica.

edit: Umm... First part reference in Japanese Link!