I think it is strange that no matter how many gems you have (and even if you end the level with 0 gems by not moving at the start) all the money is still used to pay the ambulance, without any money coming out of the money you already have (if there is no money), and no money going to you (if you got to a higher level like diamonds, or rubies without saving any money)
Who knew that the hospitals were the real gougers in this game?