Well, let's do some process of elimination. Robert? He didn't drink the shot, IMO. His emotional sensitivity has made him very happy, and as far as we can see, he suffered no downside. He even reached out to arrange the meeting.

Tom? He's a professional jock with a boyfriend. Not an easy place to be. And I got just a whiff of his boyfriend's unease. I think he worries that Tom is keeping him a secret and might keep doing so. So, maybe bowed to peer pressure and drank.

Bill is an equally likely candidate, I think — worrying about the social consequences of being trans.

I can't make a final elimination, actually. I'd say God might have known in advance, but if She can't predict the future, I guess we all have to wonder.