A thing in which Ryuutaro joined in - with some elegance of course.
He was not fully sure what was even going on anymore, but if it all was as it seemed, it could not be very good.
Younger versions did have this tendency to be weaker then their future selves (when the future self was not already an old man, naturally, but that was not the case here).

Ryuutaro was still so very lost on everything happening in this world however.

So WTF-facing along with everyone was probably the only thing he could do right now.