You may prevent a dangerous situation. Do exactly as the robber says, keeping your movements short and smooth to avoid startling the robber. You will be able to give a better description. Do Not Resist. Cooperate for your own safety and the safety of others.
Robbers usually are excited and perhaps easily provoked.
Tell the robber about any possible moves you have to make, or that someone is in the back room, etc. Try to give him the bait money if this can be done without the robber knowing. Activate an alarm if it can be done secretly. Know how to activate it by touch. Use the Witness Assistance form to help with your recollection.