I think the OP is confusing some issues. Drills are quite common, and they have all kinds of crew drills including fire, man overboard, etc etc. As to ambulances, its quite common to have some folks get sick or even die (there are morgues on most ships) on cruises. You have thousands of folks, and many of them are up in years. One nice thing about getting sick on a ship is that there is always at least one physician, nurses, and some pretty decent facilities. Help is only a minute away as opposed to many land vacations when you can be hours from a decent hospital (try traveling throughout Egypt). Although there are times when you can hear a page for medical, most of the time the medical teams are called-out by beeper and/or their cell phones.