10 Best Time-Loop Sci-Fi TV Episodes
7. Marvel’s Agents Of S.H.I.E.L.D. - “As I Have Always Been”
When the S.H.I.E.L.D. Agents find themselves trapped inside a time vortex, only Daisy Johnson and Phil Coulson are aware that they are stuck in a loop. The two work to save everyone before the ship explodes, resetting the loop. If Daisy dies in the attempt, she loses all her memories of the loop.
This results in Coulson having to brief her on what's going on multiple times across an unknown number of loops. They attempt to bring Jemma Simmons into the fold but find that her memories are being suppressed by an implant, so they try to deactivate it.
This results in their deaths, and it quickly becomes apparent that a saboteur is keeping Daisy and Coulson from removing it. They learn that it's Enoch, who was programmed to protect the implant at all costs for the safety and sanity of Simmons, which presents a problem, as Enoch isn't easy to beat in a fight.
It takes several attempts, but they finally manage to subdue him and remove the implant. Simmons instantly remembers that Enoch's electrochron displacement mechanism can repair the damaged time drive and collapse the vortex, so he freely gives it up, knowing he will die as the loop is broken.