WARNING: The following contains spoilers for What If...? Season 1, Episode 1, "What If... Captain Carter Were The First Avenger," streaming now on Disney+.
One of the most questionable decisions in Captain America: The First Avenger came when the Hydra spy tried to steal the super-soldier serum from America's test run of Project Rebirth. The operative waited until Steve Rogers was hooked up to the machines and turned into Captain America to make his move and steal the serum. Despite setting off an explosive, however, it was a massive mistake because, even as he fled, he allowed Cap to come into play. Well, now, in What If..?'s first episode, the operative's error is fixed, only it's to no avail.
In the alternate reality of "What If... Captain Carter Were The First Avenger," the Hydra spy doesn't wait for the experiment to get underway, which is a smart move on his part. He fires shots at Dr. Erskine off the bat, even hitting Steve in the process, while grabbing a vial so he can get the serum back to his bosses.
This was the right course of action because if the elixir works, Hydra would have the means to create super-soldiers, while America would need to seek a new test subject. And if Steve didn't make it out alive, it's possible his replacement may not have been the man he was, so ultimately, this strategy is one filled with foresight.
Unfortunately for Hydra, the spy couldn't have predicted Peggy Carter would stay on the floor rather than go up top to watch the proceedings. With her in close proximity to the assailant in this new reality, she's able to save Steve from death, stop the spy and take part in the experiment to become America's first super-soldier.
Ultimately, one spy wasn't enough for a mission this big. Even Howard Stark, were he not a coward, could've taken the serum if Peggy weren't available or unwilling. In truth, no matter what reality the Marvel Cinematic Universe heads to, the stage is always set for America to get its Cap, while Hydra is left with nothing.
To see how Hydra fails in its mission to steal the serum, the first episode of Marvel's What If...? is streaming now on Disney+.