What kind of tools would you need to dump the ram of a locked macbook with disc encryption on? Seems like a pretty advanced microsoldering job. Facilities, equipment and skill requirements would limit this to extremely high profile investigations surely?

Not yet. My focus was getting the computer locked. I hope to add that or similar functionality that will remove the disk keys in the future.

Right now it looks difficult to implement. There's no instant "purge keys from RAM" command and shutdown is slow. Maybe aiming for a similar state to logout might be a good middle ground? Logout locks the keychain and kills apps.