Hi cruisingtime and welcome to Cruise Chat.
Since each ship is a city, there are bound to be incidents and accidents that occur that require the attention of specialized teams onboard. I've been on cruises where "Team A" was called for a "Code Red." This turned out to be a crew member who slipped in the kitchen and required attention. Last year on the Queen Mary 2, an announcement was made that anyone with Type A+ blood was asked to please go to the infirmary. We found out a passenger had an accident and they thought they'd need blood for him. A hundred people volunteered, but it turned out they didn't need to take anyone's blood. The passenger was evacuated from the ship at our next port of call in the Caribbean.
Most incidents are minor and controllable on the ship. I once heard a team being called for what turned out to be a minor kitchen fire. Every incident is taken very seriously and must be reported. Thankfully, most are minor with no injuries. The ambulance may have been there as a precaution, if someone was experiencing chest pain, or fainted, or whatever.
A web site like the one f-mattox mentioned may have the report up eventually.