As a nurse in training, if there was physical injury(say you broke your leg pretty bad, need pins, rods all that), you would technically be discharged but may immediately go into rehab(known as inpatient rehab). So, taking it with a grain of salt, she likely didn't have any immediate grievous bodily injury and instead it could be a lower grade of injury and or may be assigned to physical therapy a certain amount of time or until function has been sufficiently deemed 'stable'(this is called outpatient rehab, the most common type).
Also entirely possible that my analyzation is absolutely wrong.