Skyhigh, you don't need to know about helicopters but you do need to have a certain amount of common sense. Very experienced pilots have told you that the equipment and personnel required for the two roles are quite different. Is that a difficult concept?
By saying that a police helicopter can be utilised as an air ambulance when not "in flight" as a police helicopter assumes an even time distribution of call-outs - this doesn't happen in reality.
Try watching Helicops or Chopper Coppers along with 999 Frontline (all featuring some of our "stars" here!!) and you might get some idea!!!
Cheers
Whirls