The only way in is with the cutting wheel or chisel pry tool or hacksaw. The Apple power adapter (brick) wasn’t intended to be disassembled. The case is glue bonded. However with the power supply inop due to a separated output wire, what was there to lose by attempting a repair. A simple splice and solder could make it serviceable once the dead section was cut out. So S’man with the Dremel Tool split the sealed case and from there the job was easy to complete. Of course the re-assembled package looks a bit ghetto.