I don't keep a whistle on me, or a bandanna. But, I do have a pocket knife in my left front pocket and my keys in the right front pocket, and a flashlight is connected to the key ring.

Does a hanky count instead of a bandanna? I keep two of them in my left rear pants pocket.

I do have a whistle/compass/thermometer combo in the outer pouch of my lunch bag. I could get to it in the dark if I had to as it sits on my desk, as long as I was in my office when I needed it.