Actually, that was no surprise at all. You could tell that Fong was a woman as soon as you saw "him" in 5.1 - the delicate face, the way "he" moved, made her gender clear as day. The only surprise is why Cullen was so stunned when he discovered Mei's identity.
But if we're willing to suspend our disbelief on this account, we still get a pretty good episode in 5.2 - in fact, one of the most powerful in the series. As I mentioned in my review of 5.1, there was lots of good, cinematic action in 5.2, which makes me think this will be a hallmark of this season. Although the talk and character conflicts of previous seasons were welcome, as was the gunplay of last season, it's good to see a story about a railroad actually show a railroad physically out of control, and our people struggling to get it back on course.
In the case of this episode, it was a railcar on a sled, in a series of life-and-death scenes in which the car is not only off-rail but nearly out of this world, and Cullen and Mei pull out all the stops to stop the car before it goes literally over a cliff.
In a nice touch, it's Mei who goes over the cliff, not the railcar, and she does this of her own volition, in a courageous act designed to save Cullen from being pulled over the cliff along with Mei. Did Mei figure that she would survive her plummet into the snow below, as she did? Or was this just luck?
Hard to say, but her near death and ultimate survival was satisfying to see, and the upshot is she and Cullen have a strong and even unique bond now. Any chance they'll eventually sleep together? Probably not, Cullen's married and all, but, then again, I was surprised when Cullen slept with his current wife in the first place.
See also Hell on Wheels 5.1: Rails and Truckee
And see also Hell on Wheels 4.1-2: Rolling Again ... Hell on Wheels 4.5: New Blood ... Hell on Wheels 4.6: Bear and Sanity ... Hell on Wheels 4.7: Why? ... Hell on Wheels 4.8: Aftermath and Rebound ... Hell on Wheels 4.9: High Noon ... Hell on Wheels 4.10: A Tale of Two Sicko Killers ... Hell on Wheels 4.11: The Redemption of Ruth ... Hell on Wheels 4.12: Infuriating and Worthwhile ... Hell on Wheels Season 4 Finale: The Buffalo
And see also Hell on Wheels 3.1-2: Bohannan in Command ... Hell on Wheels 3.3: Talking and Walking ... Hell on Wheels 3.4: Extreme Lacrosse ... Hell on Wheels 3.5: The Glove ... Hell on Wheels 3.6: The Man in Charge ...Hell on Wheels 3.7: Water, Water ... Hell on Wheels 3.8: Canterbury Tales ...Hell on Wheels 3.9: Shoot-Out and Truths ... Hell on Wheels Season 3 finale: Train Calling in the Distance
And see also Hell on Wheels: Blood, Sweat, and Tears on the Track, and the Telegraph ... Hell on Wheels 1.6: Horse vs. Rail ... Hell on Wheels 1.8: Multiple Tracks ... Hell on Wheels 1.9: Historical Inevitable and Unknown ... Hell on Wheels Season One Finale: Greek Tragedy, Western Style