My Hero Academia chapter 404 saw Bakugo and Deku together saving All Might. While it seemed like the former no. 1 Hero was drawing his last breaths, the UA academy duo together saved him from the clutches of All For One. However, this would not have been possible if it weren't for one of the former One For All users' quirks - Gearshift.
The fight between Deku and Shigaraki has been going on for some time. With that, Deku is bound to have gotten exhausted. However, just as when All Might was in danger, and Bakugo was prepared to help him, the current OFA user was willing to risk it all by using the Gearshift quirk to launch Bakugo toward All Might and All For One.
Disclaimer: This article contains spoilers from the My Hero Academia manga.
My Hero Academia chapter 404 sees Deku disobey the Second User
After Katsuki Bakugo made his return, he immediately knew what he had to do. Upon learning that All Might was in danger, he flew towards Deku, knowing that the current OFA user could launch him faster toward All Might and All For One.
Just as Deku caught Bakugo and was about to launch him, the Second User warned him not to use his Quirk: Gearshift. The blowback from the Second User's Quirk was bound to leave Deku exhausted. Thus, the Second User asked him only to use the Quirk if he was confident that his plan would work.
As fans saw, after Deku launched Bakugo using the Gearshift, he could reach All Might in time and save him. This series of events shows that Deku was willing to bet on Bakugo to save All Might, as he wanted to win without making any sacrifices.
However, the same seemingly isn't the case for the Second User, who was not adamant on keeping everyone alive but doing what was best for everyone. Considering the risk of saving All Might, he was willing to sacrifice the former No. 1 Hero to conserve Deku's energy to fight the villains.
While this may seem cynical to the fans, the Second User's decision-making may have been affected by the fact that he had already passed away while trying to defeat All For One in the past. Hence, he may no longer want to witness the cycle repeated, so he may have wanted to prioritize defeating the villains over saving others.
As evident from a conversation between the Second User and Yoichi Shigaraki, the Second User had previously sacrificed many people's lives to ensure he could defeat All For One. Unfortunately, he failed at his task.
However, that is different from the kind of people Deku and Bakugo are. They are both heroes who want to be victorious, all while ensuring everyone survives. As Deku could trust Bakugo, he was willing to risk it all by using Gearshift on him. Fortunately, the duo combined their strengths appropriately, saving their idol.
This could be a sign that things were about to change. Unlike the previous generation of OFA users who were willing to sacrifice their close ones, the new generation of heroes wanted to keep everyone alive. This change in attitude could likely be why the heroes might win against the villains in My Hero Academia.