For a research assignment, a student records these notes from a source. Notes from the source: 1. A safety planning source reviews evacuation drills in a science museum. 2. Visitors included families, school groups, and people using mobility devices. 3. Drills revealed that some exits were hard to find when exhibits were crowded. 4. The source argues that drills test not only alarms but also wayfinding, staff roles, and accessibility. Which choice most clearly summarizes the source's central idea about evacuation drills?