Chances are by now, you have already seen Marvel's biggest,baddest superhero movie yet Avengers: Infinity War and the movie also probably left you with some big unresolved questions. You may have even picked a particular hero to blame, though it's clear that there's really no single person at fault as most everyone in the movie made very emotional choices.
But the one character who's motivation look a little strange is Dr Strange himself. In the movie he told Tony straight-up that he wouldn't hesitate to put the Time Stone before the lives of everyone but in the end he finally choose to save Tony by giving up the Time Stone. An Infinity Stone that, given its manipulative properties, all but guaranteed Thanos a victory.
But why did Strange choose Tony over the fate of the universe? Is it because over the course of the movie,he grew to like and appreciate Tony as a person and partner as they fought side by side against Thanos? Lets find Out his Strange plan.
!
Source
If you have watched the movie u'll remember, before Thanos arrived on Titan, Strange looked through over 14,000,605 futures and saw only one outcome where they'd won. It was a bit of magic that we'd previously seen Tilda Swinton's Ancient One perform back in the Doctor Strange movie. That also means he’s looked at every single move in the one victorious timeline that will lead to Thanos’ defeat. Therefore, he can plan ahead. Thus, it stands to reason, allowing Thanos to kill half the universe will ultimately be Thanos’ downfall.
But as bad as it might seem, that might be necessary. Think how heartbreaking Peter Parker’s death was, and how much it will affect Tony Stark. Something like that will drive him to get revenge and put a stop to the Mad Titan alongside any other plans he has for the universe. Especially when you consider that Doctor Strange offered Thanos the Time Stone to save Tony’s life, someone he only met a few hours previously. Clearly, in the one future that Doctor Strange foresaw a victory, Tony Stark is essential in saving everyone and defeating Thanos.
Once Strange surrendered the Time Stone in defeat, he announced that they had entered “the endgame.” Unfortunately, he turned into dust without sharing the details of what he was up to with Tony Stark, who Thanos kept alive thanks to that deal. But Doctor Strange is a wizard with many tricks up his sleeve, so trust that he’s about to pull a big rabbit out of his hat.