Did John Walker inject the serum?

John Walker injected himself with the last remaining vial of Nagel’s serum shortly after being given the mantle of Captain America. As the serum enhances one’s inner traits, it exacerbated Walker’s mental instability, causing him to become significantly more violent and cruel.

Did John Walker jump on a grenade?

Bucky Barnes : You ever jump on top of a grenade? John Walker : Yeah. Actually, I have. Four times.

Is John Walker returning?

In an interview with Collider, Russell revealed that he knows absolutely nothing about when Walker might return to screens. Despite the character being expected to return in the likes of Captain America 4 and the recently announced Thunderbolts movie. “No, you never know. They do a really good job of keeping it secret.

Is John Walker still Captain America?

After a short fight with Sam and Bucky in the aftermath of episode 5 in which Sam eventually takes the still-bloody shield from him, Walker is brought back to the US, stripped of the mantle of Captain America, and discharged from the military.