That shield was collecting dust in his workshop. Tony regretted that now, because it'd be put to much better use here. And it would have with Thanos too, he was sure. He didn't regret demanding it back at the time, but it still stung that he'd had to in the first place.
Just another thing he didn't care to think on, not right now. Especially when he couldn't make it right.
"That's a terrible saying," Tony said, looking unimpressed in the low firelight. Sometimes he missed the glow of his reactor, too. The reassuring blue light that meant he was alive and nothing was quitting on him, not yet. Sometimes he still woke up, terrified to realize it was gone. "You're not that much of a nomad. Or you weren't before, anyway."