its my guess that she/he is looking to spawn/attract a mate. this the main reason they dig. they looking to make a nice spawning bed. This the main drive of there life and dictates there actions.
As of yesterday he still wont eat. I did a large water change and still nothing. I did notice that there are no MTS when the tank was full of them before he went in. Wiki mentions Midas eat snails in the wild, maybe mine has been eating all the MTS in the tank.