The thought of testing Her, giving Her a taste of Her own medicine is perhaps the most exciting aspect of this whole strange time-warp thing.

He opens the door, allowing GLaDOS and Chell to traverse the catwalks to the next test chamber.

"You know how it all works, so I don't need to bother explaining it to you. But I'm thinking, now that you've actually got legs for testing that we could, ah. Do this ...cooperatively. Sort of shake things up a bit, so we're not doing the same test chambers from...before."