My guess is that it's very unlikely for either Shay or Tracey to win the money. Shay has too much to lose and Tracey doesn't have enough to lose to get to the magic 50% mark in the time that they have.
Also, Abby has been talking on FB about her injury. Apparently it's an ongoing deal. There's a photo on FB of all the women taken in front of the Mexican Food restaurant they went to in Week 4 and Abby is on crutches in the picture.