It's all speculation for now. I was at the mercy of the Maho Camera operator and he/she kept zooming in and out to follow the landings. They didn't waste anytime scooping the person up off the sand however. They were there and gone within minutes - lights flashing and with a police escort. There was a large crowd of people on the beach and the incident happened very close to the end of the runway.
A couple of years ago we were at Maho when a young French girl was hit by the jet blast. I think she was hanging from the fence and went tumbling backwards striking her head on the concrete barrier. Not far from her was another young person who had a head injury. She was the most badly hurt but I read later on (on TTOL)that she had recovered.
We love Maho Beach but it can really be dangerous - especially for cruise ship passengers who have never been to Maho before. Five years ago I had to help a young father with two children under the age of 3 get away from the jet blast of a departing 747. He had no clue and was standing right behind the plane. I pulled him and the children away just as the 747 powered up and took off. He only spoke French but he was so grateful. I was shook up too!!!!