Limits
Mach 4.
Three thousand miles an hour.
On a good day, at least.
It's easy to read the statistics from a bland, impersonal file and accept them as fact - God knows that Clint had.
And it's not that it's not true. Pietro had just proven it in a mad dash from one end of the country to the other, providing them with the key ingredient they needed to defeat the bad guy, save the day, win the fight.
What Clint hadn't been able to understand from the bland, impersonal file was just how much that the feat would take out of Pietro.
As the others took the weapon out of Pietro's shaking hand with barely a thank you, their minds already focused on the task ahead, Clint couldn't tear his eyes away. From Pietro, who looked like he was about to keel over, sweat drenching his clothes, his breath coming in great, heaving pants that made Clint's own chest feel tight in sympathy.
Wanda, looking as concerned as Clint felt, stepped forward just as her brothers knees gave out, his weight falling against her and threatening to take them both to the ground. Clint wasn't even aware of moving but suddenly the weight of Pietro was in his arms, his skin rapidly cooling, the drying sweat making it damp and sticky to the touch.
"I got ya, buddy." Clint whispered into damp, sweat-soaked hair, Pietro's head lolling senselessly against his shoulder.
For the first time since joining SHIELD, Clint was willing to let the others handle the day saving without him. There are more important things than being the hero.
Maybe the damn kid will realise that some day too.
Until then, Clint would make damned sure that his file is updated to say that while Quicksilver can run at Mach 4, even he has limits.
Limits that Clint was going to do his best to recognise and make sure that they don't get overstepped again.