Though foreign soldiers in the Rhodesian Army were only required to immediately commit to three years' service, Coey volunteered on arrival for at least five. He joined the Special Air Service (SAS), an elite commando unit. He was one of several foreigners in his barrack room, and they decorated their quarters with the flags of their home countries. Coey performed well during his initial training, and was recognised as one of the Rhodesian Army's top recruits of 1972; after passing out in November that year with the rank of trooper, he was picked out in January 1973 for instruction as an officer. While training for this new role, he contributed articles to various Rhodesian and South African publications, sending work to the latter under the Afrikaans pseudonym "Johann Coetzee". The political and religious views reflected in his journal continued: on 18 September 1973, he expressed profound joy at the overthrow of Chile's Marxist President Salvador Allende, and painted the incident as a victory for Christianity and the West.