A classic "people trapped in a lift" story from Russell T Davies that was exceptional for its very tight direction and superb acting. The argument scenes were brilliant feats of vocal choreography, reminiscent of the spoof Christmas piece done by David Tennant and Catherine Tate.
These are very talented people doing a very good job indeed.
Overall I was amazed at how such a simple set up just whizzed by so quickly. Never a dull moment!