Which of the following is NOT advised during an active shooter incident when barricading?

The choice of using soft walls for concealment is not advisable during an active shooter incident because soft walls, such as those made of drywall, do not provide adequate protection against gunfire. The primary goal during such a situation is to maximize safety, and hard barriers that can withstand bullets are much more effective for protection.

In contrast, locking the door, hiding behind large, solid objects, and silencing electronic devices are all well-supported strategies that enhance security and stealth. By locking the door, you create a physical barrier that helps delay or prevent the shooter from entering. Hiding behind large, solid items offers better protection compared to soft items, which could easily be penetrated. Finally, silencing electronic devices reduces noise that could alert the shooter to your location, allowing for a quieter and safer environment until help arrives.