From my point of view there are two ways of passing over, represented by the two groups:
- Yuri is the rebelious and self building one. Basically, like the buddhist monks, you work on yourself, solve your problems and get to know yourself to the point of enlightment, thus passing over.
- Tenshi, on the other side, is the social passing over. Basically, instead of working on yourself and try to know yourself by solitude and rebellion you heal your wounds in society and try to use the comunication with others to understand yourself, thus passing over.
The first one is harder, and that's why so few people were able to pass over on the Yuri group (even though it doesn't seem like they have such big problems, being that she said at the beginning that a few of her people disappeared when they tried to blend with the Tenshi group).
The second one is easier and more natural so that's why so many people disappear in the Tenshi group. Because of that Tenshi thinks she is right, so she tries to disband Yuri's group, thus allowing the member of the SSS to pass over.
My 2 cents.
