Warning: SPOILERS for Snowpiercer Season 2, Episode 6 - "Many Miles From Snowpiercer"
Melanie Cavill (Jennifer Connelly) stole Snowpiercer from Mr. Joseph Wilford (Sean Bean) and she made the right decision to save the future of humanity, despite everything it cost Melanie, including her daughter Alexandra (Rowan Blanchard). Snowpiercer season 2, episode 6, "Many Miles From Snowpiercer" was a revolutionary hour that was entirely about Melanie's solo mission to the Breslauer Research Station. For the first time, Snowpiercer depicted what Melanie and Wilford's relationship was like before the Freeze and what drove Cavill to take the train.
The survival of what is left of the human race is a burden and responsibility Melanie chose to carry since before Snowpiercer began. In season 2, Melanie discovered the Earth is miraculously warming, and that there is a chance that there could be areas of the planet that Snowpiercer's passengers could colonize. This required getting the abandoned Breslauer Research Station in the Rocky Mountains online; a mission only Head Engineer Cavill could undertake - and Wilford delighted that it was potentially a suicide mission for his sworn enemy. Melanie left Snowpiercer but lost her rations due to an avalanche, forcing her to nearly starve until she discovered rats living in the walls of the station she could eat. But far worse was the mental and emotional toll the month-long ordeal took on Cavill as she faced her inner torment, which manifested in versions of Wilford, Alex, and Andre Layton (Daveed Diggs) she imagined conversations with.
The most jaw-dropping moments of "Many Miles From Snowpiercer", however, were the flashbacks. The first took place in Chicago before the Freeze when Melanie and Joseph celebrated the completion of Snowpiercer's Eternal Engine, which Melanie designed but Wilford took public credit for. A second flashback set during the construction of the Nightcar saw Melanie confront Wilford about his denying her team of geneticists passage on the train in favor of stocking his private army of Jackboots. As Wilford showed his true colors - he's more interested in creating a private world he could rule with an iron fist than altruistically trying to save the human race - Melanie realized what her boss was capable of. Mr. Wilford's viciousness was on full display in the final flashback set the night Snowpiercer departed Chicago when Wilford ordered his Jackboots to cold-bloodedly murder Melanie's geneticists. Egged on by Bennett Knox (Iddo Goldberg), Melanie stole the train while Wilford was outside, despite Alex and her family not making it aboard.
Melanie always believed that had Wilford controlled Snowpiercer from the start, the Great Ark Train wouldn't have survived one revolution around the planet, and she is quite likely correct. Even as the master of Big Alice, Wilford has shown that he prides his own creature comforts above the well-being of his people and he manipulates, intimidates, and kills to achieve his ends. Of course, Melanie was forced to do many equally terrible things in Wilford's name when she ran the train, but Cavill was also concerned with finding ways to perpetuate humanity - the development of the Drawers was Melanie's Hail Mary attempt to cryogenically preserve key passengers to repopulate the world if Snowpiercer failed (which she believed it inevitably would).
"Many Miles From Snowpiercer's" intriguing flashbacks showed that the cruelty and selfishness beneath Wilford's charming veneer haven't changed one iota. Melanie made an impossible choice when she took Snowpiercer from Wilford and she's still paying for it since she keeps being separated from her daughter. Perhaps the best episode of Snowpiercer thus far, "Many Miles From Snowpiercer" was a deep dive into Melanie Cavill's deep-seated guilt and fears, but it also highlighted her determination, resourcefulness, and capacity for self-sacrifice.
Cavill is routinely faced with unenviable decisions to make and she rises to the occasion, even (and especially) when it personally hurts her the most. The irony is Melanie's heroism may have tragically cost her the chance to reunite with Alex aboard Snowpiercer. Meanwhile, without his nemesis Melanie aboard, Mr. Wilford is closer than ever to taking back the 1,034-cars-long super train he believes belongs only to him, potentially dooming everyone aboard Snowpiercer in the long term.