Incredibly fleet of foot and prone to singing as they killed people.

From Small Wars, Faraway Places by Michael Burleigh. Page 186.

Aboriginal intermediaries were rewarded too, stocking up on such goods as refrigerators and radios, without realizing that they needed electricity to power them. After 1957 the insurgency lost its anti-colonial aura with the establishment of an independent Malayan government under Tunku (Prince) Abdul Rahman, and by the late 1950s CT activity was confined to Kedah and Perak near the Thai border. One of the final major operations concerned a Communist leader called Siu Mah, who had led the group that killed Sir Henry Gurney. He and his group had been holed up in caves in limestone cliffs, severely short of food. Two of Siu Mah’s three bodyguards sent to contact the Min Yuen for supplies instead surrendered to Special Branch, under a plan already hatched with a third bodyguard who remained with Siu Mah. A Chinese Special Branch officer, posing as a member of the Min Yuen, accompanied the two turncoats back to the caves. As they arrived they rang a bicycle bell twice, the signal for the remaining bodyguard to assassinate Siu Mah.

Life in the jungle involved contracting horizons, so that the main preoccupations were food and somewhere warm to sleep. The wider world was represented, if at all, by crackling voices on a radio. Early CT camps were large, with the days and nights packed with an orderly round of activity. Iron discipline prevailed, and commanders awarded merits and demerits for bravery or dozing off while mounting an ambush. As the larger formations gave way to small bands, the rigid discipline seemed gratingly petty-minded. Worse, the delusion of being a cog in a huge machine (present whenever messages came from the South Johore Regional Committee or the Press and Propaganda Unit) gave way to the reality of being like animals on the run, pursued not just by the British, but by Dyak head-hunters, fierce black tribesmen from Nyasaland with arrow-shaped initiation scars on their faces, and beefy Fijians, incredibly fleet of foot and prone to singing as they killed people.