After he requested active duty, Vincent was sent to assist with the defence of Singapore and the Dutch East Indies Campaign. In February 1942 he took command of the combined Commonwealth fighter formation, No. 226 Group, which had only two Hurricane squadrons, along with the remnants of Brewster Buffalo units, at Palembang, Sumatra. Outnumbered and poorly-equipped Commonwealth and Dutch units fought a losing battle against overwhelming enemy forces and in March, Vincent was evacuated to Australia, where he advised on air defence systems. He was then appointed Deputy Chief of the Air Staff by the Royal New Zealand Air Force, a post he held for nine months.