 Gradually, he spent more and more time on operations with the Combat Corps of the Irgun (the HaK, "hayil kravi"), and as a result ended his university studies.In many operations, Haviv took on the job of machine gunner, mainly participating in attacks on the British police's Criminal Investigation Department (CID) in Jerusalem and on the government income tax offices, as well as in mining operations in the Jerusalem-Bethlehem area against British security traffic.On January 19, 1946, Haviv participated in a joint Irgun-Lehi attack on the Central Prison in Jerusalem's Russian Compound in a failed attempt to free Jewish underground prisoners, in which two of the raiders and a British soldier and policeman were killed.