I would suggest that the DUmmy take a 16-pound slegehammer and strike the mirror repeatedly until it no part of it remains on the wall.
Another method to loosen the adhesive would be to thoroughly soak the drywall and baseboard below the wall with kerosene or paint thinner, then
carefully ignite it and wait until the heat softens the adhesive. The mirror can then be removed without breaking.
Alternatively, one could approach the mirror from behind, in the adjoining room. Carefully cut out the drywall in the area of the mirror. After a hole is cut,
giving access to the back of the mirror, the sledgehammer can then be used to force the drywall and mirror off the studs.