After spending more than half a decade building up Thanos as the Infinity Saga’s end of level boss, Avengers: Infinity War needed to make sure that the Mad Titan lived up to the hype. Any doubts were dispelled by the end of the very first scene though as the genocidal maniac beat the Hulk to a pulp with his bare hands and killed off popular Asgardians Heimdall and Loki before the action had even reached Earth.
Using his final moments to pull off one last act of heroism, Heimdall summoned the Bifrost and sent Bruce Banner rocketing back to his home planet, even though two of his fellow Asgardians were in the same room, with Thor trapped and Loki attempting to get close enough to Thanos to strike a killing blow. But why was it the Hulk that he chose?
Well, a new theory explains why Heimdall decided to save a complete stranger at the expense of two people that he’d known for thousands of years, and it makes absolute sense within the context of both the Marvel Cinematic Universe and Infinity War itself. Obviously, there were no guarantees that Loki wouldn’t just vanish and try to hide from Thanos the second he was clear, so he was never going to be the candidate to warn the Avengers of the impending threat of the Mad Titan, especially when he’d previously tried to enslave the human race.
Thor, meanwhile, had already watched half of his race be wiped out, but Heimdall would have known that the hero would never willingly run away from a battle. And given Banner’s close connections to key Avengers like Tony Stark and Steve Rogers along with his genius-level intellect, he was in a much better position to lay down the facts than a vengeful God of Thunder was.
