im actually gonna disagree with the reply you got before i saw this as i disagree with alot of info he had provided you.. he is correct that a monitor can never really be completly trusted but i disagree they cant be "tamed".. monitors are extreamly smart and just ask any keeper who has had numerous monitors for more then a few years and they will tell u there are some that will want to eat your face and some who will relax next to you.. iv personally seen both.
as for the monitors out of the cage.. its the same idea of u handling a snake for 4 hours is bad.. for a few min to an hour is not gonna hurt em... iv read actually read numerous accounts where monitors and tegus have been aloud to free roam a room with there enclosure door open and had no ill affects.
so i do disagree that a nice or "tame" monitor is unhealthy simply becuse iv seen monitors who are both healthy and nice.. a member on another forum had a 7ft nile who was 14 years old who he would let roam his house and never had a problem.. as long as the knowledge and respect are there then there is no reason u cannot have both a healthy tame monitor