Desmond meets Abigail and Theresa Spencer

Desmond Hume tracks down the home of Theresa Spencer, the woman in the photo with Daniel Faraday. Her sister Abigail answers the door wearing a Quikmart vest. After Desmond says he got Theresa's name from Daniel, Abigail invites him in. Desmond is shocked to find Theresa in a hospital bed being fed by a nurse/caregiver. Abigail says that Theresa is "away" right now. She says sometimes she wakes up and thinks that she's three years old and "yesterday she was talking to our dad" who died five years ago. She also says that Daniel ran off to the states and abandoned Theresa. Abigail reveals that Charles Widmore funded Daniel's research and covers Theresa's medical and living expenses. Apparently Theresa became the subject of Daniel's experiments which led her to this state.

Why did Daniel use Theresa as a test subject? Did Charles Widmore convince him to? Also, why did Daniel leave for the United States after Theresa ended up in this state? It seems that Thersa is experiencing some similar side effects as George Minkowski and Desmond but with out the eventual death. It seems that Theresa has managed to slip in and out of time without, well dying. I'm sure this isn't the last time we'll hear about Theresa.