I think the ball would go to the keeper:
11.4 Table Maintenance - Any necessary table maintenance, such as changing balls, tightening the men, etc., must be requested before the start of the match. The only time that a player may call a table maintenance time out during a match would be in the case of a sudden alteration to the table, such as a broken man, broken screw, crumbling bumper, bent rod, etc.
11.4.1 If a player figure is broken while in contact with the ball, an official time out will be declared while the rod is fixed. Play will resume on the rod where the player figure broke.
11.4.2 If the table lighting fails, play shall immediately stop at that point (as though an official time out were called).
11.4.3 Routine maintenance, such as spraying the rods, etc., should only be done during time outs and between games.
11.5 Foreign objects on field of play - if an object should fall on the playfield, play shall immediately stop at that point and the object shall be removed. Play shall resume from the rod where the ball was when the object hit the playfield. There should be nothing on the ends of the table that could fall onto the playfield. If the ball is in motion it will be put back into play by the player who had last possession.
11.5.1 If the ball comes into contact with a foreign object on the playfield that was overlooked play shall stop and the object shall be removed. Play shall continue at the rod of possession when play was stopped.