Steve / Tony
Anything that was going to get to Tony was going through Steve first, acid or anything else. He'd lost him once and the image of that haunted him at night, kept him up sometimes, standing back and watching him turn into dust on a breeze. A great man, the greatest Steve had ever known, it tore him up to think about and he wasn't going to let anything like that happen again.
Steve could see Tony's point, the technology wasn't like that The Guardians had, or anything as high tech as Nebula. It looked more like the ships you saw on old TV shows and that didn't go filling Steve with confidence. Steve's personal nightlight did a pretty good job lighting the way and his eyes adjusted quickly to the low light.
It was too quiet, with that disconcerting feeling they were moving and Steve paused, stopping Tony too. He stayed still, listening carefully, sure he'd heard something. "I don't like this," Steve said seriously.