Steve lets out a soft little bark of laughter, but he immediately pulls the lid off his cup and holds it out for Yelena to dole out a dose for himself.

It's frustrating, losing the serum, but there is some small amount of compensation, he supposes.

"Sorry," he adds, though his wry, lopsided smile says he's only a little sorry. "That's me, asking the questions that require the strong stuff to answer."