The phrase " Shelter-in-place " has also erroneously been used , instead of the more accurate '' lockdown '' , to describe precautions to be taken by the public when violence has occurred or might occur ( particularly in shootings ) in the area and the perpetrator is believed to still be in the area but not apprehended . The public in the area is advised to carry out all the same tasks as a typical shelter-in-place but without the key step of sealing the shelter up to prevent outside air from circulating indoors , in this scenario people are simply urged to lockdown — stay indoors and " close , lock and stay away from external doors and windows . " In light of active shooter events and the panic that can ensue , a lockdown alert issued as " shelter in place , " can also be implemented as a response to armed events , such as the 2014 Fort Hood shooting . Similarly a lockdown alert was likewise issued as a " Shelter-in-place " alert by the Massachusetts Emergency Management Agency over the cell phone Wireless Emergency Alerts service for local residents during the manhunt for the Boston Marathon bombing suspects
Boston Marathon bombing
Boston Marathon bombing
Shelter in place