Gun, Knives and a dose of reality
First this a snap shot in time, a very small glimpse at one force on force scenario.
The student in black started out with his protectee (guy in red behind him, picture your wife or kid) on his reaction side walking down the street, so far so good.
He is then confronted as he turns the corner by a man with a knife ordering him to give up his wallet. Our good guy uses his reaction side arm to move his protectee behind him but due to the dynamics to the situation the protectee is now moved to the good guys strong side. This causes three things-
His first instinct is to now get his right hand up to reestablish physical control of his protectee, this becomes exaggerated now because instead of being off to his reaction side his protectee is behind him causing him to stumble backwards. As he falls to the rear both hands come out to the side. His right arm also seems to be pinned against his body hampering a possible draw. This is when you will need open hand skills. The bad guy already spooked advances with the knife.
This did not end well for the good guy.
There is no perfect answer to any of this, I post it to show how with step this way or that way the dynamics of a situation can change dramatically.