Yeah, it was a big surprise to us, too. But I think she used the other situation to her advantage to distract Cole (there were a few situations he should have been involved with but wasn't because of her "spazzing out"), and it explains probably how she was able to avoid time and change her name etc. from her tawdry past. Besides, they always end up having a mole at CTU - why should this season be any different? You'd think they would do better background checks by now....
I was so happy Chloe finally grew a pair and took a page from the Jack Bauer book.