The meaning of the word 'ambling' as used in the passage is to WALK OR STROLL. In the passage, the author is saying that, he finds it distasteful to strut before a small child who is walking or strolling in a relaxed manner. The meaning of the word 'curtailed' as used in the passage is to BE DEPRIVED OF SOMETHING. The author is saying in this line, that he is deprived of beauty.
It would be rainsford falling off the yacht because at that point you wouldn't know what is going to happen and that eventually turns into a series of events.
