When the robber asks the store employee to open the register she simply says “No, don’t open” then walks out, and THEN gets the woman with the baby to join her outside while she locks the robber in. She doesn’t try to fight him, doesn’t take matters into her own hands: simply jingles a few keys and pops open a cold one on the sidewalk and waits to see how long it takes him to realize he’s trapped in there. Dude even tries shooting the lock to get out.
Finally, the police arrive and takes his dumb ass to jail.
Remember, choices have consequences!