Follow-on.

The drill was part of an urban scenario for an IED explosion or suicide bomber attack.

The whistle is to sound 3 short blasts if you are trapped in rubble, to direct attention of large crowds or to signal further danger.
The knife is to cut stuff as/if needed.
The flashlight is to find your way in a powerless room/hall in the dark and to signal for help.
The bandanna is to either cover your face from the toxic dust or to stuff into a bad wound. Sterile is not needed to stop bleeding.

The drill was based on experiences in Iraq and Isreal and included such tidbits as "secondary" attacks that are timed to kill first responders.

It turns out that there's a lot of survivability fairly close to these incidents for many people.

Anyway, one of the interesting points was that a cell phone=a flashlight for many people, and bandanna can serve fairly well for airborne particulate matter that can have severe (fatal) long term health consequences. A wet bandanna is even better.

A great lesson.