Is adoring our Lord in the tabernacle and adoring him exposed on the altar the same thing? Why is it necessary to have at least two people there?
No, they are not the same. The difference is that the Blessed Sacrament is underlock and key in the tabernacle. When it is exposed it is vulnerable to vandalism. So at least one person has to be on guard there. It’s better to have two. I spend my daily hour before the Blessed Sacrament in the tabernacle. It’s the same Lord who is present there.