Conundrum of a fire alarm with gunfire: Flee, or lock down?

A fire alarm that was sounded during a Florida high school shooting this week added to the chaos of the day.

When a fire alarm goes off, students typically flee the building. During active shooter situations, they hunker down in classrooms.

Both scenarios occurred in Florida, creating a dilemma for students and staff.

Emergency responders say there is no single accepted set of best practices for responding to active shooter situations, and the protocols vary dramatically from district to district around the country.