"Yes," he slowly admits. ".. Everyone does."

As much as Inigo likes to pretend he's okay no matter what, even if he's by himself, he knows that's not the truth. He would completely collapse without friends by his side. Especially in a situation like this, where someone so important to him is most likely about to leave.

"So I'm taking that as you saying you don't mind having an extra one here on this train?" It's the most roundabout way possible to ask to be friends, sure, but Inigo is trying to keep the tone light here. If not just so he doesn't start crying on the spot all the same.