Shion is so happy to have someone to chat science with, you have no idea! Even if their systems are completely different, the fact that they share the enthusiasm and mindset is enough. On a more personal level, she trusts Van and feels relaxed around him. It's worth noting that her canon fiancee has more than a few personality trait in common with Van... She doesn't really age-discriminate in her interactions, but she's still surprised how much of a relief it is to have someone in her own age group to bond with. And their memory pact has helped her make a dent in the backlog.

Reverse?