The handgun does not necessarily have a safety. Also, many people will keep a round loaded in the chamber so that they can respond to threats as quickly as possible. Draw and pull the trigger. Leaving the gun in your car probably doesn’t fit in with this strategy, though. I think mixing these circumstances with a toddler is pretty fucking stupid.
The strength required to pull the trigger will depend on what kind of gun it is, and how they’ve configured it with the springs inside. A double action revolver will usually require lot more force and travel than a semi automatic pistol.