BB is not in a great position vs. Law. Law and crew have a plan that will let them escape: the sea, Law's crews' knowledge of the sea, and all of BB's crew have df. Those issues were blatantly foreshadowed.
OT somewhat, but in many ways it seems BB is getting anxious. Normally, he waits for the right moment to strike. Why didn't he wait until someone had all of the Poneglyphs and then struck with his complete crew at a place that is to his advantage?