Most probably the authorities are using this SAR (search and rescue/retrieval) as an exercise to dig deeper into the unknown and undocumented underground maze of utilities. They may not find an intact body but they may learnt a lot during these few days of searching. You can say the search is in a few limited areas but what they discovered in the underground labyrinths is enough to give them an inkling of other areas in KL.

but why ambulance on standby ya ?

My guess is that the he restaurant needs to be cleaned due to hahal certification and make their Muslim customers more comfortable.
Meanwhile this place no halal cert.