Please see this interesting news from a Nan Tah alumni website. It made some interesting speculations as to why Mr Lee Kuan Yew wanted to demolish his home after his passing. This is a brief English translation I wrote.
"One important reason why Lee Kuan Yew wishes to demolish his 38 Oxley road home is because it has a secret tunnel leading direct to the Istana. This is a secret that surfaced many years back and it was used by Lee Kuan Yew to avoid the busy traffic congestion and to ensure his personal safety when he goes to work.
This tunnel is a source of worry for Lee because refilling the tunnel will be costly and it was a matter of time before the tunnel was discovered by others. Once discovered, people are bound to question the existence of the tunnel and how much taxpayers money were spent building it. Why did the building of the tunnel not pass through Parliamentary approval and who authorized the building of such a tunnel?"
The original chinese version is found in the link below.