Remove the rumble pack by prying up on the corner next to where the rail once was with a spudger. Once out of its socket, use tweezers to pull the cable connector out of the socket. It is inserted quite firmly so be careful not to hurt the cable and use your fingernails if needed

There is some mild adhesive holding down the rumble pack so take care not to damage the rumble pack. Additionally, do not remove it fast enough to hurt one of its connecting cables if it suddenly breaks free