I think very likely, he had help. This looks like a very well-planned 'Prison Break'. The people who helped him probably have knowledge of police procedures. So they anticipated what the police would do and that's why he was able to evade capture during the first day.
Any ex-National Service man would know that our uniformed personnel are very good in following SOPs - Standard Operating Procedures. All our contingency and emergency plans are preplanned and laid out in great detail. For example, when I first performed the battalion duty officer function, I had to familiarise myself with various operational plans for various disaster scenarios; such as a plane crash. Even though this was three decades ago, I think the operational style would still be the same. Thus it wouldn’t be difficult for Mas Selamat’s helpers to find out the kind of procedure the police will take once his escape was discovered.
Like YG, I think he would have headed for Bukit Brown cemetery, which is quite deserted. He would have met his accomplice there, changed into jogging gear and cross over Lornie Road and hide in the MacRitchie Nature Reserve which is linked to the Bt Timah nature reserve. Here there are plenty of places to hide, and where food and clothing can be left behind for him.
Hence, I don't understand why during the first few hours, the police concentrated their search in the Malcolm Road and the Dunearn Road areas. Afterall, in order to get to Malcolm Road, he has to cross a very busy Pan Island Expressway, one way or another. Could it be because they were worried that this guy would catch hold of some school kids from St Joseph's Institution or Singapore Chinese Girls School and used them as hostages?
If Mas Selamat had indeed escaped to MacRitchie Reservoir, it would be quite ironical. On the very same afternoon of his escape, I was at MacRitchie Reservoir, and I saw many police personnel and vehicles there for some kind sport event.