Take a hammer and a flat tip screw driver and hit it down the middle! You can break it into as many pieces as you want but I wouldn't go too small. Maybe break it in half and break up one half into smaller pieces or break it into fourths and see how it recovers. Should be fine though.
Go through the back.
Remember the tool will get extremely hot. Be careful not to cook the coral!
Work slow and patiently.
After fraggimg, the Hydnophora exesa will be very vulnerable to KH/Ca swings, so watch your dosing!