SPOILER WARNING: This article contains major spoilers for “Finish Line,” the Season 3 finale of The Flash.
There were many heart-stopping moments in the Season 3 finale of The Flash, with the first shockwave coming in the episode's opening moments as Savitar struck down Iris West. However, before fans could mourn her loss, Team Flash discovered HR Wells switched places with her, thereby changing the future.
In "Infantino Street," last week's episode, HR mistakenly told Savitar that Iris was hiding out on Earth-2. After Cisco gave HR some words of wisdom, the episode showed the Team Flash member glancing down at the leftover piece of Savitar's armor from earlier in the season. Using it as a homing beacon, HR was able to find Savitar's lair and free Iris. During their escape, HR used the face-swap technology he brought over from Earth-19 to switch his and Iris' appearances.
Right as Joe West broke down at the sight of his daughter being stabbed through the chest, HR came to him on the rooftop and revealed himself to be Iris. Back on Infantino Street, HR made the same reveal to a shocked Flash, before whispering his final words for Cisco to the Scarlet Speedster.
HR sacrificed himself to save Iris because he felt that it was his fault she was kidnapped in the first place. HR was constantly portrayed as intellectually inferior to previous versions of Harrison Wells throughout The Flash's third season, but -- by swapping his life for Iris' -- he finally proved that he was an indispensable member of the team.
It's also worth noting that, if it wasn't for Cisco's encouraging words to HR, he wouldn't have summoned the strength to make his ultimate sacrifice. Barry Allen revealed this very thing to Cisco at HR's funeral. Out of every supporting character on The Flash, Cisco has always had the closest relationship to the Harrison Wells of the multiverse. Though HR and Cisco constantly butted heads, their friendship not only saved Iris, but also highlighted how HR was the show's greatest Wells yet.
Starring Grant Gustin as the Scarlet Speedster, The Flash will return this fall on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.