George is offering drinks to Sammy at a party. Sammy graciously accepts and then decides to take two giving the reason that he'll know that he's not seeing double.
This must be George and Lynne's party. However George could be one of those people who offers to help at someone else's party and then gets lumbered with a job for the rest of the evening. In this case, making sure everyone has a drink. He is doing a bang up job and with a smile on his face to boot.
He has remembered the first rule of Sammy at a party and that is never let him out of your sight. He has however forgotten the second rule which is never offer him a drink. The moment Sammy takes the second drink, 'Mantha's sixth sense kicks in and she looks towards Sammy in shock.
When Sammy gives the reasons for taking the second drink the faces of his friends tells the full story. 'Mantha is not so much upset but disappointed in Sammy. She realises there is nothing she can do for him and will no doubt be resigned to leaving him. Lynne looks at George with an inkling of blame, but just to get his attention to what is happening to their friends. George looks at Lynne with apology. He knows he has done something wrong, but in some ways they all knew it would happen.