It's a feature of ObjectScript (perhaps widely known, perhaps not) that if you open the same object ID multiple times, you end up with the same OREF. For example:
USER>set obj1 = ##class(Sample.Person).%OpenId(1)
USER>set obj2 = ##class(Sample.Person).%OpenId(1)
Generally speaking, this is an important feature - you won't end up accidentally modifying the same record via multiple paths and losing some of the changes.