//As long as 'drastic measures' don't involve alienating the scientists in general, then do what you need to do, sure.
//For clarification, I have no personal problem with you pursuing or not pursuing adventure times with Rika. Lord knows I've done that and plenty more throughout the course of the game. I believe it would be to everyone's benefit, however, if you approach what appears to be a dicey situation with concern for how Yumemi must feel right now. Rather than argue with her and rebel for the sake of rebelling, it would be better to work things out calmly and be willing to make reasonable concessions as appropriate, in the interest of both you getting your girl and the rest of us not losing the scientists as friends. And, if things do go south, don't be surprised if other players start jumping in to try to defuse the situation while holding the group friendship with the scientists as higher priority than your romantic pursuits with Rika.