S1·E5 Inescapable Darkness

The Kotetsujyo picks up survivors from Yatsushiro Station which has been destroyed by the Kabane. Among the survivors is Enoku, an old friend of Mumei's. He points out to Mumei how weak she'd become as he witnessed how close she's grown to the people of the Kotetsujyo. Rattled, Mumei chooses to throw herself into a reckless fight and finds herself in a dangerous situation.