Big Sky by Jorge Michel Grau

4.37

Hazel suffers from a crippling case of agoraphobia - so much so that it causes a rift between her and her mother, Dee. They agree that Hazel will go to a treatment facility to help her deal with her fear, transported by a driver and specialty van from the facility. But when two masked gunmen attack them on the desert road, Hazel has to battle her fears so she and her mother can survive.