Fmr. Newtown teacher responds to Ben Carson In her book 'Choosing Hope,' fmr. Sandy Hook Elementary School teacher Kaitlin Roig-DeBellis describes how she hid her first graders in a bathroom during the Newtown school shooting. She also joins Ari Melber reacting to Ben Carson's comments on arming teachers.

The Last Word with Lawrence O'Donnell on MSNBC