After episode three upped the pace and the stakes, this latest episode sees further movement with our titular Slow Horses scattered and in a cat and mouse game with the upper echelons of Regent's Park trying to stop the escaped terrorists who have fled the scene and avoid entanglement with Diana Taverner's footsoldiers. What ensues is a thrilling episode full of close shaves, showing the resourcefulness of both sides of MI5 as our heroes look to outsmart their seniors. Even with the thrill-a-minute stakes this episode still manages to capture the human side of these characters showing their vulnerability and desire to come out on top, once again impressively finding room to give each character some development and purpose with an expanded role for the ever brilliant Saskia Reeves as Catherine Standish who has been a relatively minor part to date but feels more integral to proceedings here. The development of the blossoming relationship between Min Harper and Louisa Guy feels wholly organic. While the series is of course a heavy drama, there is a place for humour scattered throughout from the more sarcastic and snarky undertones of Jackson Lamb to a gag about Min's car CD player being stuck on a particular Coldplay track. One can hope the final two episodes help the series stick the landing and give it the ending it deserves, with several narrative threads left to untangle and with several of the Slow Horses in a precarious position - not to mention the matter of the terrorists and their kidnapped teenager to resolve.