Thanos ended Avengers: Infinity War as the clear cut winner, but the Avengers missed a few golden opportunities to stop him. Josh Brolin's Mad Titan finally got a proper introduction in Infinity War after being teased in The Avengers and appearing in a brief role in Guardians of the Galaxy. He ultimately succeeded in wiping out half of the universe's population, leaving the remaining MCU heroes mourning the heavy losses.
In Infinity War, several heroes made the choices they deemed to be their best chance at stopping Thanos. Doctor Strange agreed to go to Titan, per Iron Man's request. Spider-Man elected to stay aboard the Q-Ship despite Tony telling him to go home. Black Panther decided to open up Wakanda's protective dome. Hulk decided not to come out. Thor famously aimed for Thanos' chest, instead of his head or arm. Strange even decided to give up the Time Stone to Thanos after seeing 14,000,605 possibilities, with only one resulting in their victory.
No matter what decision was made by the various heroes, Thanos' goals were still achieved. This will lead to the surviving heroes trying to figure out the best course of action to reverse the snap in Avengers 4. But, if they had tried some alternative plans, they may not even be in this position. Here's a few ways the Avengers could (theoretically) have stopped Thanos in Infinity War.
- This Page: How Heimdall Or Doctor Strange Could Have Defeated Thanos
- Page 2: Just Don't Go To Titan!
Heimdall Sends Thanos Into Deep Space
If a quick defeat was going to come Thanos' way, there's a chance Idris Elba's Heimdall could've been the key to it all. When Infinity War opens, Thanos and the Black Order have already taken command of the Asgardian refugee ship. Only Thor, Loki, Hulk, and a wounded Heimdall remain to try and combat the Mad Titan and his comrades. Thanos' power is put on display quickly as he beats down Hulk without even needing to use the Power Stone, but it's what happens almost immediately after Hulk's defeat that could have been used as a way to take down Thanos.
Heimdall uses dark magic to open the bifrost and transport to Hulk to Earth. This was Heimdall's last act before dying, but he could have made it out alive if only he had used the same tactic to remove Thanos from the vessel. Transporting Thanos off the ship alone may not have been enough to truly defeat him, as he could theoretically still find a way to return from wherever Heimdall sent him. But Guardians of the Galaxy, Guardians of the Galaxy Vol. 2, and a later moment in Infinity War all show how quick death can come to those who are exposed to open space.
If Heimdall sent Thanos out into space instead of a specific location, he may have died in the same way that Ebony Maw did. It is possible the Power Stone would've been able to possibly save his life somehow, but death by space maybe should've been attempted. However, even if Thanos can survive in true space, it may have still been worth a shot to at least buy more time - while finally giving Heimdall a major MCU moment, instead of a quick death.
Chop Thanos' Arm Off With Magic
Not many have had any luck fighting Thanos one on one, but Doctor Strange did hold his own. The Sorcerer Supreme used his magical skills to combat the various threats Thanos sent his way, but Thanos was also able to do the same with the power of the Infinity Stones. Strange may not have used the Time Stone to actually fight Thanos (as far as we know), but one of the other spells he did looks to hold plenty of potential to take down the Mad Titan.
The first spell Strange is able to conjure with his sling ring in Doctor Strange is opening a portal that rescues him from the freezing temperatures of Mount Everest. The portals can do more than just transport people though, and Infinity War was sure to remind viewers of this early on. When Iron Man, Doctor Strange, Wong, Spider-Man, and Bruce Banner fought Ebony Maw and Cull Obsidian in New York, Wong opened up a portal to transport Obsidian away from battle. But, when the giant child of Thanos attempted to jump back through, Wong closed the portal and cut off Obsidian's hand in the process.
This appeared to be major set up to many, but it isn't a move that the Avengers even consider. If Wong can do this, than surely Doctor Strange can as well. We'll never know exactly why this action wasn't taken, but on paper cutting Thanos' arm off with one of these portals would instantly make it impossible for him to proceed properly. We do see how difficult it is even draw a drop of Thanos' blood, so it is possible that his alien skin is so tough that the portal wouldn't cut through it - but that seems like a stretch. Perhaps Wong (if he's still alive) can try this in Avengers 4.