Despite being pinned, the Female Titan hardens her skin, preventing Levi and Miche from cutting out the human pilot.

In a shocking tactical move, the Female Titan allows the surrounding mindless Titans to devour her own body, creating a massive cloud of steam that she uses to escape in a Scout uniform. Leadership and the Philosophy of Change

Season 1, Episode 20, is widely regarded as one of the most defining moments for Commander Erwin Smith. It marks the transition of Attack on Titan from a story about survival into a high-stakes psychological game of wits and sacrifice. The Hidden Objective

The expedition is ultimately called off as a failure due to the high casualties and the escape of the spy. The episode ends on a tragic note as the cloaked mole, still hidden among the Scouts, ambushes Levi’s squad and kills Gunther Schultz, setting the stage for the devastating battles to follow. 57th Expedition Outside the Walls | Attack on Titan Wiki

While the official goal of the 57th Expedition was to secure a route to Shiganshina, Erwin’s true motive was a high-risk gamble to flush out a spy hiding within the military ranks.

Only veteran Scouts who had survived for five years or more were briefed on this true mission to ensure that any potential mole was kept in the dark. A Game of Wits: Capture and Counter-Strike

This episode highlights the brutal utilitarianism that defines Erwin's leadership. As Armin Arlert famously notes during the mission:

"Those who can't abandon anything can't change anything. If there's anyone who can bring about change, it's someone capable of giving up what matters most."