Dr. Sanjay Gupta gets exclusive access to a wounded soldier shot during the Ft. Hood rampage. This interview provides a chilling look inside the shooting: Crawling and being dragged to safety by a nameless fellow soldier, then struggling to survive his wounds. Find out why Army Specialist Logan Burnette says he feels pity for the alleged gunman. Then, virus hunters believe they've found the origin of one of the planet's deadliest diseases -- we're going into the jungle as they track a virus. And, meet doctors making health care work on their own terms -- including making house calls for no extra cost. All this -- and how your cholesterol levels could raise your risk for Alzheimer's disease.