In the preview released last night at the conclusion of the The Walking Dead, Andrea is seen in a clip from next week's episode holding her gun alongside the Governor and telling him, "I saw them."
It's unclear (and unlikely, given the riot dispersal grenades and the like) whether she actually saw the features of the attackers and understood that it was her old friends, but one thing sticks out: the gun.
After the events of last year's midseason finale, it's been widely expected that something big and traumatic would happen in this one. Given Andrea's aggressive new personality over the last few episodes and her role in the comics as the top badass sniper in Rick's group, it's not hard to imagine her taking somebody out during their escape attempt, exacerbating the war between the survivors and Woodbury and giving her (especially if she recognizes who she killed) ample angst to carry her through the rest of the season.
It's hard to guess what will happen with Andrea, and with the raid in general. The most drama seems to be in teasing out a handful of reveals as long as possible to keep them hovering over the characters's heads, particularly the Governor's. That Michonne is still alive and out there would really rock his world, and his faith in Merle. The revelation that Woodbury is going to war with Rick and his group would likely put Andrea in a bad place. The showdown between the Dixon brothers is something everyone is waiting for. These and other stories could plausibly be kept under wraps EVEN as the attack on Woodbury happens with flash-bangs and gas obscuring the view of the battlefield and keeping the right people from seeing the right things at the right time.