The fact that a alligator came on the runway is’nt just unpleasant because of the delays, but it makes in the worst case the airplane crash. The main reasons why there could come an alligator on the runway is that first of all : it is Florida, Florida is famous because of the large number alligators live there. The second reason is : that the airport consists of 110 hectares water surface. So there are many alligators hidden there. They could prevent comparable incidents by placing fences around the water.
Here you can watch the recording of a passenger on board.