One of the most tragic characters in the Marvel Cinematic Universe and its source material is Dr. Bruce Banner (Mark Ruffalo). His lowest point is shown in Avengers: Age of Ultron, following a run-in with Wanda Maximoff (Elizabeth Olsen), who hexes his mind, making him Hulk-out and sending him on a rampage across South Africa. The event left the reluctant hero shaken to the core. He eventually left the team at the end of the film, but the reason why he abandoned his friends after Ultron's defeat was never really explained.

Nevertheless, an extended scene on Disney+ may shed some light on what was going through Banner's mind. Following his battle with Iron Man and his Hulkbuster suit, the Avengers retreated to Clint Barton's (Jeremy Renner) home, a farm in the middle of nowhere that he had to keep his family hidden and safe. There, the Avengers were able to collect their thoughts and pull themselves together after Wanda forced them to face their fears, such as Natasha (Scarlet Johansson) reliving her time as a spy in the Red Room.

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The deleted scene, "Bruce and Natasha Talk," followed the two heroes, who were finally able to share some alone time. In the scene, Natasha tried her best to express her feelings to Bruce, but he was far too focused on the damage he caused as the Hulk. He felt that he was too much of a threat to innocents, and there was no place left on Earth where he could have lived a normal life. Like Natasha, Bruce felt like he lived in a fantasy world as an Avenger, and that the mistakes of his past weren't able to catch up to him. However, the moment he lost control, the façade crumbled, and he knew that nothing had really changed for him.

Hulk in Avengers: Age of Ultron

Bruce's plan from that moment was to leave the team for Natasha's benefit and his own. While Natasha might have gone with him if he had asked, she also knew that she was going to be needed so long as people were in danger. This was proven later in the film, after Banner rescued her from Ultron. Rather than run away with him, she pushed Bruce down a hole to bring out the Hulk for the final fight and to save Sokovia's citizens. Even though he stayed to defeat Ultron, Hulk wasn't there for the celebration, as the last time he was shown, he was in a Quinjet leaving the team behind.

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In the theatrical cut, the Bruce's decision to leave was loosely foreshadowed by his hesitance to become the Hulk again. Even so, his departure came across as drastic because the film didn't spend enough time showing how his loss of control impacted the character. In contrast, the deleted scene revealed that Bruce was so haunted by what had happened that he was more than ready to go on the run again and leave everyone he cared about behind.

Avengers: Age of Ultron showed the team at their most unified before everyone went their separate ways in the end. But Bruce's departure turned out to be the most tragic thanks to his clarified motivations in the film's deleted scene. As the scene showed, he felt that he didn't deserve to be happy and that the Hulk was a danger to everyone on Earth. These beliefs eventually drove him from his friends.

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