Here are a few passages from the book (“The Singapore Story: Memoirs of Lew Kuan Yew”) relevant to the question:

“…I believed then that the discipline of the students and the energy and dedication of their leaders were natural and spontaneous, born of youthful enthusiasm and idealism. It took me two years from 1954 to 1956 to fathom their methods, to get glimpses of their intrigues and deviousness and to understand the dynamics of the communist united front (CUF). Behind the scenes, the anonymous Town Committee of the MCP controlled and ran open front operators like Robert Soon Loh Boon and those section leaders at mass rallies. The communists had a secret network of disciplined cadres grouped in cells of about four, each with a leader who gave the orders (dressed up as the outcome of democratic discussion), who in turn took orders from a leader in another cell of a higher rank. These orders were disobeyed at the risk of isolation and marginalisation for those on the fringes, of rustication and punishment for those who were members of the Anti-British League or the MCP, and of death by assassination if a party member had committed an act of betrayal. It was a ruthless system in which a past record of sacrifice could count for nothing, and therefore not one to be defied lightly…” (113)

“…But at that time I, too, got carried away by the wave of sympathy for them, and on 20 September, the Nanyang Siang Pau quoted me as saying, ‘Until now the authorities have no evidence of any communist activity in the Chinese schools; but they regard opposition to the government’s refusal to allow the students postponement of service as communist activity, and under this pretext, they seek to exercise better control over the Chinese schools.’ I was ignorant, gullible and stupid. I did not know just how efficient the communists were, how their tentacles reached out and controlled every single organisation that was bubbling up against the government.” (114)

“The biggest single theme that galvanised the Chinese-speaking was Chinese culture, and the need to preserve Chinese traditions through the Chinese schools. It was not a proletarian issue; it was plain, simple chauvinism. But the communists knew it was a crowd-winner that pulled at Chinese heartstrings, and they worked on it assiduously.” (122)

“Goode now explained that the Emergency Regulations were necessary because murder, arson, acid-throwing and other crimes of violence were part of the communists’ bid for power. They had to maintain their acts of terrorism not just against the military, but also against civilians in order to cow them into a conspiracy of silence. The result was that no one who valued his life would appear in court as a witness to any communist-related crime.” (128-129)