Yesterday, I went to the newly opened Jurong Point 2. It is brightly lit and shops are opened. While I was right outside NTUC Xtra, I am still able to get a 5 bar reception on M1 network. Once I move further in, I am practially with no signal coverage. The phone just shows "For emergency calls only".
SO, if you happen to be at Jurong Point, tell us if your other operator, e.g Singtel, Starhub has any coverage inside NTUC.