Mezue ahịrịokwu na-esonụ: A họpụtara Callinan ka ọ bụrụ onye isi ndị agha na Citizens Military Force na June 1940, a họpụtara ya na Royal Australian Engineers. Na Machị 1941, ọ wepụtara onwe ya maka ije ozi na mba ofesi wee sonye na Second Australian Imperial Force, na-ewere ọkwa dị ka onye nkuzi na Demolitions Wing, na 7th Infantry Training Center. E buliri ya n'ọkwa onye isi n'ọnwa Julaị afọ 1941, ma mesịa ziga ya dịka onye nke abụọ na-achịkwa ndị &lt;a href="2/2nd%20Commando%20Squadron%20%28Australia%29"&gt;2/2nd Independent Company&lt;/a&gt;, na-eso ha aga
Timor dị ka akụkụ nke Sparrow Force na Disemba 1941. O mechara duru ndị ọchịagha n'oge ha na-eme mkpọsa n'àgwàetiti ahụ na July 1942 ka e bulie ya n'ọkwa nke obere oge.