Big Sky (movie, 2015)

Hazel suffers from a crippling case of agoraphobia. So much so that it causes a rift between her and her mother, Dee. Hazel and her mother decide to go on a road trip to a desert facility to help Hazel deal with her fear but when gunmen and brothers Jesse and Pru attack them, Hazel has to battle her fears so she and her mother can survive.