He frowns - but in that way that makes it obvious that Inigo is thinking. He was already thinking, trying to figure out how to fix their current half-tethered situation, but his thoughts shift a little now. It's a lot of thinking, especially for a guy not particularly bright like Inigo, but..

What else is he supposed to do? He can't just sit around and wait for someone else to fix their situation. And if Senku's world is in trouble, then he wants to help with that too, because he can't just abandon any friend in trouble.

"I don't think the train would have done something directly." At least, Inigo.. assumes so? He doesn't even like the train, but he figures it wouldn't have time to mess around with worlds while it's flying around through the void.

"If anything, it probably has something to do with your absence there. Didn't that pink-haired girl on the network say a few days ago that the Ministry told her that her world was gone, and she said it was because of her absence? Or.. something like that." Inigo reaches up with one hand to pull said hand through his hair, still thinking. He didn't quite know the details, having found the broadcast too sad to respond to. "Maybe something about you being gone from your world made the situation worse? Though I'm not sure.. how."

Especially since it's not his own world. He knows some stuff about Senku's world, but certainly not enough to piece together exactly how him being gone could turn everyone back to stone like that.