It sounds like you fly at this location regularly, and I would assume that you had a plan for the scenario, or one simliar, prior to the recent event as you said you were instructing at the time. It sounds as though you made the right decision, and who knows how it might have turned out if you chose the other. Did you have life jackets on at the time, and did you follow your pre-conceived plan or was it off the cuff at the time? Being that your options were a rock and a hard place, prior preperation to assist in the unfortunate event is probably the best thing you could do.