In WWII, an Australian soldier removed his own appendix in the middle of a Philippine jungle in 1944, without any anaesthetic and with only the use of a mirror and an ordinary knife. The operation took 4 and a half hours and he stitched himself up with jungle fibre.
Following the end of the war, McLaren was discharged from the AIF and transferred to the Reserve of Officers List in early 1946. Following this he became a government veterinarian in New Guinea. He remained in this role until 1956 when he began growing coffee, buying a plantation at Wau. On 3 March 1956, McLaren was accidentally killed when rotted timber fell on him near his home after he backed a vehicle against a dead tree.