But in the season 3 finale tonight, we find out a much specific reason: she's pregnant with Bohannan's baby (she says she's 18, by the way), and Bohannan figures that marrying her would be a way of getting out of the noose that her Morman father had planned for him. And Bohannan, in a wild twist, figured that right.
Not only that, but the Bishop who marries them is none other than the Swede. No one knows the truth of what he did - only the son, who is with Ruth and the railroad. The Swede decides that he would rather let Bohannan live, so he can subtly torture him over the years. A wild ending in itself.
But not only that - Elam, on his way to save Bohannan, gets attacked by a bear. Eva is sure he is dead. I'd say not - Hell on Wheels would be crazy to kill offf such an important character.
And, with Bohannan nowhere to be seen, Ulysses S. Grant has no choice but to acquiesce in Durant's reappointment to run the railroad.
All of which sets up a powerful last scene. Bohannan is farming, thirsty. His wife wants to bring him water, but the Swede takes the water instead. In the distance, we and Bohannan can hear the railroad. Elam and the bear are both stretched out, unconscious. I'm betting Elam will rise and the bear will not.
The haunting thing about that last scene is that Bohannan, married with a child on the way, has found part of what he always wanted. We'll see how it turns out next season, which I'm hoping will rise up as well.
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
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