Even with magazine out and no round in chamber, a firearm must always be considered as "loaded" and handled consequently. Let's brush up on the safety rules.
The first rule of gun safety must be taken literally even if you risk to look stupid. Of course, if the slide is held open, the chamber is visibly empty and the magazine is out, a firearm can not fire – but the rule is more about bad habits to get rid of than you may think. Repeated movements are unconsciously assimilated and then executed even when tired, unfocused, or under stress.
No distinction should be made between a loaded and “unloaded”. If a shooter tends to put his or her finger on the trigger of a firearm and “muzzle” accidentally people or objects when a gun is visibly unloaded and clear, those inappropriate movements can be repeated unwittingly – and dangerously so – when the gun is loaded.