Stark is of the same mindset. He's shouting at anyone who will listen that something bigger is coming. Phil believes him because as grandiose and ridiculous as Stark is Phil's rarely seen him afraid. He's afraid of whatever's out there. It seems like Clint is too.

"I'd let Natasha recalibrate your cognitive function a second time if you did." As understandable as the sense of defeat might be that's not who they are. They keep going against the impossible.