What is the most logical next event?

How to confront someone who's giving you the silent treatment
Consider what else is happening in their life.
It could be that they're not actually giving you the cold shoulder. Maybe they, or someone they care about, is ill or having personal problems.

OPT: (I) Maybe they're moving to another country and the silent treatment isn't working. Or maybe they weren't devastated when the person left. (II) You won't know for sure until you ask them, but if you notice they seem more withdrawn with other people, too, it might not be the cold shoulder at all. If you notice a really severe personality change and other mutual friends do, too, talk to the person immediately. (III) An adult who wants to treat you like a friend is unlikely to give you the silent treatment. However, they do want you to feel comfortable communicating your problems with the person, so if this is the case, asking them to trust you again, especially the night before, is probably a good idea. (IV) Whatever the issue is, try to ignore it and get past it. Decide what else bothers you and why.
(II)