Put on a long-sleeved shirt, work gloves and protective eyewear. Tile shards are sharp so take the proper precautions to avoid flying debris.
Attach a diamond- or carbide-tipped cutting blade to the Fein MultiMaster tool.
Power on the MultiMaster. Move the cutting blade slowly back and forth in the grout surrounding the corner tile. This cuts through the tough grout and exposes the corner tile.
Turn off the MultiMaster tool and remove the cutting blade. Attach a flat scraper blade to the MultiMaster.
Power on the MultiMaster. Push the tip of the flat scraper blade underneath the corner tile. Move the scraper blade back and forth beneath the corner tile until the tile pops free.