I totally get that you want to find out what happened when you lost time but instead of jumping to conclusions and making assumptions you should do some actually digging and maybe a little fact checking.
Retracing your steps is a great way to remember those things forgotten but when you don't see everything, the next course of action is to not accuse someone of murder but to asked them to be straight up with you because the last thing you do remember is them telling their best friend that they should kill someone. Someone, who as far as you know is a human. (She wasn't, she was super friggin' crazy!)
I don't know. I just think that before he got all in Drake's face and was being all ominous talking about about "I know what you did.", he should have actually tried to find out what happened that night. Ever since his dad, the terrorist, said that he left the party with "the big Atrian" he's been on this whole Drake-did-something-to-me-and-he-must've-killed-Zoe kick. Not fair, especially since he knows Roman was there.
It seems I was right. Grayson was going to do something stupid. Just not about the quasi break-up between he and Emery.