There's a part of Sam that wants to keep shooting until the sound of gunfire drowns out the words - wants to sink his talons into their broodbond and shove his way in - but he pulls back. Whatever progress they've made, whatever strides they've taken in their relationship and their brood bond and everything else, the trigger words are always going to be their biggest threat.

Sam didn't need the reminder to know that, but it does make him regret not acting immediately on the idea of saying the words themselves.

When Bucky scrambles and struggles, Sam doesn't hold him back, but he doesn't let go of him, either. He stays by Bucky's side at the edge of the tank, and this time his tone is softer.

( I won't leave you alone. )