A Shelter In Place plan is selecting an interior room or rooms in the building with no or few windows, and taking refuge there (USDOL, 2018). In many cases, local authorities will advise to shelter-in-place for the protection of people through the media. This would be the case if it is safer to remain indoors due to chemical or airborne poisoning chemicals, or unsafe grounds. There are situations on site that may result in a decision by an employer to institute shelter-in-place if there is an an explosion nearby, or a derailed and leaking tank car of chlorine on the rail line behind your place of business (USDOL, 2018).
Most likely it would be safest in an Assisted Living Facility to use a Shelter in Place plan as most residents may have trouble getting around. In a time of panic or danger this could be even more dangerous to them or their health. This would be based on the danger and urgency of getting individuals to safe areas.