Ken-chan might speak English but Romeo doesn't so there's a flash of confusion at those words that he doesn't understand.

But Romeo understands that look, Ken is thinking. And he's thinking about Big Questions.

It's confusing he knows, so he gives him a moment, though he does add.

"You can ask anything you want, though I might not know all the answers!"

But if he doesn't, they can find someone who does. There's lots of smart people on this train.