"No Way Out" is considered the highest-rated episode of The Walking Dead for several reasons. The episode is the midseason premiere of the show's sixth season and is particularly notable for its intense, action-packed storyline. The episode features the survivors of the zombie apocalypse battling against an overwhelming horde of walkers in Alexandria. Viewers were captivated by the suspenseful and thrilling sequences of the characters fighting for their lives and the survival of their community.

Additionally, the episode marked a turning point in the series as it showcased the characters coming together and fighting as a united front against a common enemy. The emotional depth and character development in "No Way Out" also resonated with viewers, making it a standout episode in the series. Overall, the combination of adrenaline-pumping action, compelling storytelling, and character-driven drama solidified "No Way Out" as one of the most highly acclaimed episodes of The Walking Dead.