Episode 5.5 [Rewatch]

[Onion Terror]

Have to say that this is still one of my favourite episodes. At the time I was still fairly new to Spooks (I'd seen a bit of series 3 but missed all of S4 due to evening shifts at work), but I remember being gutted at Ruth's exit. For me this episode shows really well the whole teams solidarity (with the exception of Ros), particularly the scene where Ruth and Zaf are waiting for the boat and Zaf promises to give her a smile if he ever bumps into her again. You can tell that he and Adam respect Ruth even more than they did before for the courage she shows in giving up her old life for the greater good. As do we as viewers.
As much as he is completely self-interested and unpleasant, I think Oliver Mace was a terrific character-a great sparring partner for Harry. Would enjoy seeing him return at some point.