From the engineering point of view, single opening saves the space of elevator shaft. But because hospital elevators need to transport beds, the width of beds should be considered.
For example, if the hospital bed is 0.8 meters wide, the two side-by-side beds are 1.6 meters wide, and the elevator should be at least 1.6 meters wide. If the elevator door is opposite, the elevator shaft must be designed as 1.6 + 0.8 + 0.8. If it is single open, the elevator shaft only needs 1.6 + 0.8 space because the elevator door can be folded. From the requirements of hospital infection control, not only the elevator door design, including other doors, are required to consider the airtight function.
The closure of two-way door is easy to lead to lax closure after a long time, while one-way door only needs to set an "e" structure to ensure the closure. You can carefully observe the doors inside the hospital, especially in the operating room, which are all opened and closed in one direction.
Even if a double leaf double opening is designed, only one leaf is opened or closed under normal circumstances. The hospital with better infection control should be from an elevator door and out of the opposite elevator door, and the elevator has the function of air shower. The first consideration of hospital architectural design should be the principle of infection control, followed by other factors.