Are Laertes and Claudius in a little competition over who gets to kill Hamlet? Like, Laertes here is ready to get back to the fighting, which gets him closer to his kill. And Claudius will not let the moment pass without this drink. Both of them must have adrenaline coursing thorugh them – they must be pretty amped up. They’re both ready to kill him at any moment. I wonder if it’s a factor in Laertes losing these points to Hamlet – he’s so focused on the murder game. And Claudius, too, who is normally so smooth, somehow cannot find a way to prevent Gertrude from drinking the poison – which, apart from killing his wife, who he maybe loves, also will spoil his plans and reveal them, too.
If I were directing this show, I’d probably explore a scene before this fight where Laertes and Claudius get themselves psyched up for this. Playing adrenaline coursing through you is not really possible but it is a huge part of having a body and what you do.