Would be really good to have at random times, events that could potentially happen outside of the hospital that would cause a mass influx of patients, for example a disease spreading throughout a small community, a fire with multiple injuries, prison riot etc etc and your hospital would have to be suitable to be able to handle such events.
Its a nice idea working up from starting at a small doctors surgery with limited space and doctors having to work on a budget to as the game progresses a huge multi storied hospital.
The integration of ambulances and possible more technical sides of the hospital i.e cleaning/catering departments, workshops, repair centres, waste / mail etc etc.