I would put the "BUG" where it was easily accessible. Kinda like I did when I carried one. But I have never been, nor could I imagine, having been in some pretty tough situations, in a shooting, trying to waste ammo by shooting both at once. I never shot below master level in qualifying in 20 years on a combat course, and it still never occurred to me to grab my BUG in the shootings I was involved in, or near shootings.
I would concentrate on gettin it done with the one in my hand. The idea sounds like good TV, if one has a vivid enough imagination.JMO