I count seven.
Did not have the pistol to hand when he answered the door, stepped away to get it.
Opened the screen door removing a barrier for any sudden hostile bodily force, which he could see through and what was going on, identify any threat, and if needed could shoot through.
Pointed the gun at them.
Told them not to leave. This could be construed as an arrest, as at this point the two could definitely have believed they were not free to go.
Stepped away to get phone which he could have had with him, or closed and locked the door to get it and make the call.
Called with screen door open removing barrier again, and probably had phone in one hand gun in the other. Not a good position to be in arms reach to two possible hostiles.
Pointed gun at them again. They would again definitely believe they were not free to leave.