Agent Barton watched from above as Doctor Banner worked on, whatever it was Clint wasn't too sure. He was hidden in a cupboard that was hidden behind a bunch of machines. It gave Clint enough room to stop him from being too cramped and the labs vents, separate from the rest of the Tower, were right above his head. So if he needed to stretch he could.
Clint had just settled himself into the cupboard again, after a quick stretch. There was some food waiting for him. He wasn't quite sure what it was or what part of the world it came from. Looking up Clint could see that Banner had turned to face him and was eating whatever it was he'd given to Clint.
They had come up with a system in which Banner could get stuff to Clint and Clint could get stuff to Banner. Doctor Banner had also set up a few objects throughout the lab so that they would reflect all possible entrances and meant that they could talk with one another if needed.
Clint had been surprised at how quickly he and Banner had worked out a shorthand, using sign language. He was just glad that Banner knew sign language. It had only taken them four hours to work out a rhythm.