Sam and Dean, along with Esther and McKay, were fighting off the angels and demons to stop the apocalypse. The boys had let the angels in in an attempt to save the women they love. Sam and Dean made the ultimate sacrifice, and jumped into a pit to keep Michael and Lucifer from destroying half the world. Unfortunately, doing so trapped them too.
Esther couldn't think. She had run after Sam when the portal opened up. Inside her mind, Xaphan was yelling. Telling Lucifer to stop, not to do it. In some part of her mind, Xaphan's screams were growing fainter. As the portal closed, Esther knew that Sam -along with Zaphan- were gone.
Esther felt alone - more alone than she had ever been. At least when she lost Lily, Sam was there. Needing physical contact, she went over to McKay, hugging her sister. McKay had lost Dean before, but that wouldn't make this any easier. Esther know that neither of them would be alright for a long time.
After a few moments of Esther crying and McKay holding her, both girls jumped and pulled weapons upon hearing someone approaching. McKay lowered her gun once she realized that it was their friendly angel.
Esther however was not in the mood for any more angels. "You," she glared at Cas, "and your messed up family killed them!" Her voice rose to a shout, shocking both McKay and Cas. Esther never lost her cool around others, and certainly never yelled.
If anyone was around when Esther lost it, it was Sam. But Sam, her fiancé, was dead. He was in a cage. With the devil. An why? Because god couldn't control the angels when they had hissy fits! And Castiel, for all his promising to help, didn't do anything. He didn't even insult his brother correctly! That incompetent... Ninny!