Curufin would understand that, that a family that is so loving and concerned could occasionally be rejecting because someone didn't live up to the norms of the family, or for some other reason. It had happened in his own clan.

Yes, a lot of emotional baggage can be invoked by a sudden departure!

"Pleased to meet you, Nike Lemercier! Yes, you're Team Blue. The train always makes sure that new passengers are wearing a hoodie in the color of the team they'll be joining. What sort of skills or abilities do you have? The train tends to assign us to a team that needs our skills."