The members and the staff thought that Pitty was checked in to a hospital because of tonsillitis. While the members still thought he was at the hospital, Pitty was in fact already checked out. 

 The members tried to get a hold of him but they got no response. Pitty has not communicated nor made an effort to  motivate his actions, even though the members have been trying to get in touch with him. 

As a result he is no longer a member of MORRIGAN.