I would propose a change to encounter that allows us to track the encounter.class for each period of time (similar to what is done with accommodations/beds).

For example, if a patient shows up in the emergency department, then encounter.class begins as emergency. However, if that patient ends up getting admitted as an inpatient, then the encounter.class changes to inpatient. Just as the patient's location (bed) over time is modeled, same should be done for encounter.class as well.