Batman v Superman: Dawn of Justice is an expert example of how well-paced storytelling can craft organic moments between characters. While not all of them impact the audience the same way, the genius in their creation doesn't go unnoticed. For example, the symbolism that makes Superman look like a god also mirrors the weight of the world he feels on his shoulders. Another excellent example of this is how the infamous Martha scene perfectly sums up an ongoing battle in the movie for Bruce Wayne's soul.
Batman v Superman meticulously sets up the impending showdown, with Bruce Wayne's hatred towards Superman growing ever since his battle with Zod in Man of Steel. He doesn't trust the Kryptonian because he believes one bad day could turn him into an enemy that can't be defeated. His anger is also nurtured in the background by Lex Luther, who wants his alter ego, Batman, to face off with Superman in a fight to the death. To motivate Superman, Lex kidnaps his mother, Martha Kent. Even though Superman tries to talk Bruce down, a battle ensues that nearly ends in the former's death until he starts begging Batman to save Martha.
Since Batman v Superman was released, the scene has gotten heavy criticism for how on the nose the delivery is and the poor explanation for how this gets Batman's character to change so quickly. On the surface, this change comes because Bruce realizes that Clark's mother shares the same name as his own. However, the film sets up a deeper meaning that is not only paid off but also justifies Batman's brutality in the warehouse fight.
Batman taking on a room full of thugs with his strength and gadgets was a battle that every fan had wanted to see for years. However, the reason that it's so engaging is due to the impact that Clark's words had on Batman. To Bruce, this is about more than saving Martha, this is about saving himself from the unthinkable. His hatred allowed his mind to be compromised and led him to make mistakes as a hero. As a result, he was more careless in saving the lives of criminals and even marked them for death.
By saving Martha, he can cleanse his soul in more ways than one. The most obvious one is that by saving Clark's mother, he can apologize for starting a fight that nearly killed Superman. However, on a more introspective note, by saving Martha, he is metaphorically saving his own mother, which he wasn't strong enough to do as a child. Not only does this help his heart heal after decades of fighting crime, but it also allows him to be reborn as a Batman who's ready for the changing world.
Batman's brutality in the warehouse fight shows that nothing will stand in the way of him saving a life and redeeming himself all at once. For Bruce, there's more at stake than just stopping Lex Luthor. To be able to continue being a hero, he has to save Martha. That being said, if he failed, it's far more likely he would've slipped further into darkness until he became more villain than hero.