Maybe one or two of the PASOK MPs could be talked into supporting SYRIZA as well. Seeing their party reduced to 4% support, it's not hard to picture a few of the PASOK survivors deciding to jump raft(we really can't call it a ship these days)simply in the name of continuing to have a political career.
It's hard to imagine any remaining PASOK'ers making the "stay the course" argument with any real conviction.