Stefan zooms into the room and pushes Damon and Elena apart as he demands to know what Damon has done. Damon says he's just saved her life. This way, if she does die, at least they know she'll come back. Stefan is furious. "As a vampire!" The boys snarl at each other about choice versus life, but as I mentioned at the outset, this is no place for politics. Stefan just doesn't understand how Damon, of all people, could take this choice away from Elena, since Damon has been hella pissed at Stefan for basically the same thing since 1864. When Elena looks up at Damon in disbelief, he says, "Go ahead. Wish me an eternity of misery. Believe me, you'll get over it." While I love all the callbacks to Damon's arc, Stefan can no longer control himself and now that he doses up on human blood, he's Damon's equal in a fight. When Damon snarls at his brother: "Admit it, you just wish you had the balls to do it yourself," Stefan pounds the snot out of him. Still, Damon bests him by staking him in the gut. By then Jenna and Alaric have joined the fun. They urge Damon out of the room, and Alaric tells Jenna where to get blood bags so that they can tend to suffering Stefan who is apologizing to Elena for not stopping Damon.
When Damon arrives downstairs, Elijah is calmly packing up his elixir, and notes that it's no longer needed since feeding Elena vampire blood has rendered it useless. And he's really sort of miffed, which tickles me silly. Yes it has rendered your elixir useless, Elijah, but can we discuss if there is another problem (besides unwanted vamping in Elena's case) with the vampire blood solution?