The: Flash - Season 6- Episode 10

Cavanagh delivers a career-best performance here, shifting between guilt, rage, and pathetic vulnerability in a single monologue. The episode suggests that Nash isn’t just mourning his lost friends; he’s suffering from multiversal PTSD , carrying the deaths of infinite Earths on his shoulders.

If the first half of The Flash Season 6 was a sprint toward the looming apocalypse of “Crisis on Infinite Earths,” then Episode 10, is the painful, exhausted stagger across the finish line—only to realize the race has just begun.

By the end, Nash discovers a hidden room in the basement of STAR Labs—a room vibrating with unknown energy. It’s a tease that promises the second half of the season won’t be about running from Crisis, but dealing with its horrific aftermath. Just when you think “Marathon” is a quiet, character-driven reset episode, the final 60 seconds drop a speedster bomb.