Team Iron Man is dangerous
So many prop-Tony stories say Team Cap are dangerous rogues. But there's actually no evidence for that. Steve stopped the illegal kill squad with no loss of life. Bucky saved himself by damaging a small bit of concrete that didn't risk the structural integrity of the bridge. At the airport, Wanda destroyed some cars, while Scott mistakenly blew up a fuel truck and destroyed a single unoccupied plane.
Team Iron Man's tally? T'Challa was out to kill. Rhodey and Tony fired explosives at people who were not wearing armor and there's evidence that Wanda's PTSD was triggered by it. Vision was a real problem. He destroyed the control tower, which would shut down an airport for months or years. He might have killed Steve, Bucky, and Natasha if Wanda hadn't held up the wreckage. Vision also fired a beam at Sam that would have killed him--if it could take out whatever was protecting the arc reactor in Rhodey's armor, it was more than strong enough to melt Sam's jet pack and the parachute underneath it. But Tony was worse. While Vision was reckless, Tony was vicious. He fried a helicopter just because, endangered Peter by bringing an untrained teen onto a battlefield, and shot Sam in cold blood. Some people suggest that Tony also made Rhodey's injury worse, because he moved Rhodey even knowing Rhodey likely had skeletal injuries.
So who really needed to be stopped?
***
After everything at the airport, Vision contemplated the pros and cons of his actions based on current results.
On the plus side, the team obeying the Sokovia Accords managed to capture four of their teammates.
But at what cost? Vision frowned as he considered the massive damage he had done to Germany's air travel. Neither passengers nor freight could be transported through Leipzig until the control tower was rebuilt.
Only now did Vision realize that he could have killed Steve, Sergeant Barnes, and Natasha. He had not bothered to calculate the potential that the heroes would keep running toward their objective, even in such dangerous circumstances.
Similarly, Vision had simply obeyed Colonel Rhodes' order. He did not consider what the beam he used to cut the concrete of the tarmac would do to Sam's wingpack. And the likelihood it would have gone through the wingpack and into Sam.
His questions seemed to pile upon themselves. Had King T'Challa signed the Sokovia Accords? Had the mysterious web slinger added to their team done so? And what had happened to the half of the Avengers who were taken from the airport?
Vision knew he could use his connection to the internet to find his answers, but he decided instead to seek out Tony to discuss his concerns.
Using Friday's link, Vision was shocked to find Tony in the middle of the ocean. He listened and watched as Tony entered what appeared to be some kind of floating prison.
He was disturbed by the conditions his teammates were in, particularly Wanda. But he held still and simply observed, even after learning how Helmut Zemo had infiltrated the government facility impersonating the dead psychiatrist.
Vision did not know what he would have done when Thaddeus Ross refused to listen about Zemo. But it disturbed him that Tony did NOT mention the Winter Soldiers.
When Tony left his helicopter and began flying, telling Friday to chart a roundabout course for Siberia, Vision decided to do the same.
***
Vision arrived in time to see Tony attack Steve and Barnes. He stepped up and blocked Tony's shots, then simply grabbed Tony's armor and held him in place.
Tony flipped open his faceplate to scream at Vision, "He has to pay!"
Vision shook his head and said, "While the news of your parents' deaths must be upsetting, Sergeant Barnes was not responsible for the Winter Soldier's actions."
Tony fired his weapons at Vision. When he made to slice Vision's arm, Vision made sure the beam passed harmlessly through his limb. He did not like to consider what would have happened if Steve or Barnes had experienced the same attack.
When Tony finally turned off the beam, Vision reached out and crushed the arc reactor.
A soft metallic sound made him realize that both Steve and Barnes had escaped through the open top of the silo. Vision did not try to pursue them.
Instead he focused on Tony and said, "I have questions."
***
When Vision found out the truth about Peter Parker, he flew Tony back to the compound. When they reached there, Vision reminded Tony that there was ample evidence of Tony's violations of the Sokovia Accords, which Vision would make public if Tony ever attempted to contact Peter Parker again. Vision also suggested Tony NOT bother to try to find any of Steve's team.
He left the compound and headed to the coordinates of the floating prison. He met Steve and Natasha as they were freeing the others. He asked to come with them.
In this universe, he kept a close virtual eye on Tony. So he called his friends for help when he learned he was in danger. Both he and everyone in this universe survived to see a happy ending.