What is one action NOT recommended when preparing to hide?

Leaving your phone on for emergency calls is not recommended when preparing to hide during an active shooter situation. This is because keeping the phone on may inadvertently create noise during a critical moment when silence is paramount for your safety. An audible ring, alert, or notification could provide the shooter with your location or attract unwanted attention.

In contrast, hiding in a locked room, turning off the lights, and pulling curtains are all actions that contribute to making your hiding place less visible and less detectable. These steps enhance your chances of remaining unnoticed by the assailant, increasing your chances of safety until help arrives.