 On 2 May the unit were planning another attack and had taken over a house on Antrim Road, when an eight-man patrol from the British Army's Special Air Service arrived in plain clothes, after being alerted by the RUC.A car carrying three SAS members went to the rear of the house, and another car carrying five SAS members arrived at the front of the house.As the SAS members at the front of the house exited the car the IRA unit opened fire with the M60 machine gun from an upstairs window, hitting Captain Herbert Westmacott in the head and shoulder.