He was one of five senior commanders on the Permanent Political Military Office of the SPLA: John Garang, Kerubino Kuanyin Bol, William Nyuon Bany, and Salva Kiir being the others.
He was senior in rank to all of the others apart from Garang, and served for four years as a member of the Political-Military High Command and as Deputy Chief of Staff for Administration and Logistics.
He almost died of thirst between Juba and Mading Bor when he and his troops travelled in an area where there was no water.
[2] Arok's wife died in 1987, and, in 1988, he visited England to place his children in school there, where it was reported that he undertook secret negotiations with SPAF General Burma Nasir.
Others killed included the vice-president of Sudan, Major General Zubair Mohamed Salih, and several other political and military leaders.