If I am using my back-up light, it means that my primary light has failed and I have "thumbed" the dive. I wouldn't be looking under any rocks, I'd be headed back/out on my back-up light.
I hold onto the light to keep from dropping it. And if I did drop my back-up light, I have a second back-up light.
I hold onto the light to keep from dropping it. And if I did drop my back-up light, I have a second back-up light.