I'm sure most of us have seen stacking cups, or those toy lightsabers that extend and retract. This medicine chest uses the same principle.
This innovation serves two purposes:
1) It allows you to pull the mirror closer to you for shaving/ applying makeup, whatever you may need the bathroom
mirror
for.
2) It allows you to store more medicine and other such items in there, just pull it out to extend it and make more room as necessary.