I second the oscillating multitool idea.. you can also buy small txt saw blades that fit in angle grinders (confident and competent users only, warning!)
If using a hole saw in a drill : either use the pilot drill and get it started cutting a few mm of the big hole, then remove the pilot drill and bore the rest of the way without, so the pilot drill doesn't ruin the socket
Or
Start out without using the pilot drill, run the hole saw at an angle to the surface so it cuts a ( shape, then as it gets deeper, turn the drill to be properly perpendicular
Or
Hole saw completely through a small bit of eg 12mm sheet wood, then place the sheet against the wardrobe wall, hold firm, place pilotless hole saw in the hole and use the sheet wood as a guide to start the hole saw drilling into the wardrobe without slipping all over the place
Cut 2 holes like what you see in the movies when the hero is looking through binoculars
Remember that you might not be able to get a plug into this socket unless you cut some more wardrobe out of the way at the bottom of the hole