Well, don't flame me. I agree the driver is at fault, but not totally.
Imagine u are the driver. In theory we all know we should give way. In practise, it may not b so easy. It may be the first time the driver kena tailgate by an ambulance. What goes on his head? It could be smth like "ok we are in tunnel, all lanes packed. Maybe when we hit expressway exit got chance to let the ambulance pass." The driver may also b thinking that the ambulance will change lane instead, given that there are occasions where lane 2 got lobang. Drivers can't predict the minds of others.
On the other hand, if I were the family of the patient accompanying in the ambulance, I would be cursing the whole traffic, not just the driver infront (unless of course it was a clear lane but he purposely refuse to give way).
My point is, we need to see the bigger picture and not just put all the blame on that one driver.
In other countries, ambulance can drive on the other side of the road. In singapore, we only have that many lanes serving so many vehicles. Is that the fault of any one person or one organization or whatever? You decide. We have barriers between opposite lanes in almost all major roads. Safety design or otherwise? You decide.
Again, don't flame me. I'm just putting things in perspective for people to think about.