While the synopsis still isn't finished, I think the spoilers gave a fairly good image of how vol 17 is going to end. So, here is a theory on what I think can happen in vol 18.

Bell and Ais (I think Loki familia is probably to help Hestia familia in the war game) team up and fight with Ottar. They manage to win. Ais and Bell share a moment, and maybe, maybe, kiss right in front of everyone. Bell's background is revealed to the world (I know I've been hitting a lot on this mark, but with the spoiler of Zeus sending a letter to Hermes, I really think this is going to happen). To me, it seems like the bomb that everyone was saying was Syr, but until now, we haven't seen a thing pointing out that that will be the case. Even more, if Freeya intends to become Syr (yes, I think that is what she wants, or at least it is somehow connected to what she wants), her identity being revealed to the world is a major problem.

So, I think that the "bomb" is really going to be the reveal of Bell's connection with Zeus and Hera. This also opens path for the "dices blown to pieces" thing. Why?

Ais and Bell share a moment in front of everyone, which would be more than enouh to make Freya lose her mind. But, if that happened, I think it would be more logical to just kill Ais, not Bell (Fulland Tale). However, a way for Freya to want to kill Bell is if her mind is completely fucked, more than it is right now. Imagine this: she sees the man she loves having a moment with the other woman he loves, and then she finds out that he is the very last descendant of the two familia's she hated. It would be the ultimate humiliation. You may say that Freya already left her grudges behind in Astrea Records, but at the time she did think Zald and Alfia were the last ones. Besides, her mental state right now is not even close to her mental state at the time. And, no matter how you look at it, Bell rejecting her love and choosing Ais is a total humiliation towards Freya. Then add the fact that he is Zeus and Hera's descendant... I can easily see her choosing to kill him.

She could look at it this way: kill him, payback for all of the humiliation, and then follow him to heaven.

Or

Just kill him.

Her change of mind will probably be Syr saying she doesn't want to hurt Bell.