The celebration in the war room was due to the fact that San Antonio no longer had to pick between Batum or Hill.
What had occurred was that when Hill came to SA, the Spurs initially told him they would take him at 26 because they liked his work-out and the connection he made. They felt he could fit in.
However, as we got closer to the draft, Batum began to slip and of course speculation over the heart grew. San Antonio now realized that Batum could be a real possibility and could eventually slip to him.
Batum came into San Antonio, got the physical, worked out, and talked plans with the Spurs.
Now, they had promised to pick Hill at 26 during his workout's, but now Batum was a real possibility. How could they pass him up? If he was at 26, then they would of selected him and still quite have possibly gotten Hill in the 2nd too.
However, when Houston came up they selected Batum, and now the Spurs did not have to break their promise to Hill or strongly debate between the both because their decision had been made for them.
If you look back at the draft, when Houston selects Batum, you can see the disappointment on his face. He was one selection away from being a Spur. The kid is even wearing an all black suit with a white/silver tie. He was ready to be a Spur and it never worked out for him.
George Hill? Well, he probably never had an idea at how close he was to the Spurs breaking their promise.