Delegate math

I just did some quick calculations using Slate's Delegate Calculator.

Here's an experiment:

• Let's say Clinton maintains a 60-40 edge in every remaining state except North Carolina.
• Assume that the North Carolina vote is divided down the middle--50 percent for Clinton, 50 percent for Obama. (In reality, Obama will likely win more delegates than Clinton here.)
  
• Finally, imagine that in the two U.S. territories still up for grabs--Puerto Rico and Guam--Clinton wins 100 percent of the vote.

The final delegate count comes to 1,609 for Obama and 1,601 for Clinton, even with these incredibly generous margins.

Why is she still in this? Does she know something that we don't?