This is a late reply, but I think it is actually possible to send the robots in two directions, at least temporarily. Say the clones started on the far left, a block was created on the far right, and then an elevator built near the left but to the right of where they started. If enough space was between the block and the new elevator, there should be some clones caught in that space that would approach the elevator from the right and the rest would approach from the left. Thus some of them should go in a different direction when they get to the top of the elevator. I haven't tested it, but it seems like it should work.
In the diagram below, S is start, B is the block, E is the new elevator created after the block. < and > are clones travelling to the left or right respectively.
0 1 2 3 4 5 6 7 8 9
1 _ _ < _ > _ _ _ _ _
0 S _ > E < _ _ < > B