beryl's death is pretty strange since mafia should usually want to keep lurkers alive. Three immediate explanations that come to mind are:
1: the killer felt beryl softed something and killed her in response. One of her only posts is "what if i'm three cops" and thats a pretty obvious contendor. I would think this points to a bulbagarden player and possibly jamie in particular. In my short time there i noticed they are really big on reading into softs and making plays based on them, and so they should probably be more likely to kill based on this than the average ZD or Px2 player would be. If taken as a soft, the post was fairly overt though, so its not as strong as it could be. I recall jamie seeming to express pride in their ability to read softs and seemed to particularly enjoy solving the game via that method, which is why they come to mind.
2: The killer wanted to kill an inactive player. I've met some mafia players like this, who feel like its curteous to kill low activity players either to make things easier on the mod (so they're less likely to need replacement) or to allow the players more engaged in the game more time to play it. I don't know who in the playerbase would match this profile, but i also think its an unlikely situation because lissi was saying she might need to replace out and was thus perhaps a more probable target for this kind of player.
3: Role mechanics resulted in the kill being out of the mafia's control. This seems feasible given what we know about the setup so far.
Jamie and the other bulbagarden players probably look worse to me considering beryl's death, although is not as telling as it could be because one of beryl's few posts suggested an information role and because mafia didn't necessarily choose beryl as their target.