If anything this is a good picture to reinforce Lock-Out Tag-Out. Generally speaking yes, but just looking at this picture I can’t tell if this is three phase or what type of power were dealing with. Additionally we don’t know the state the contactors are in, if this is industrial equipment then without more context there’s no way to know what each set does. Perhaps one of the contactors is hot while the other was shorted to ground when the mouse touched it. Maybe it’s not wired right, there’s a lot we can’t know from a picture. Also I really hope that you LOTO whenever you are working on electrical equipment.