If it was 'toss bombing' (close to what we used to call the F-111's precision in my day
) it would involve a pull-up and half-loop some distance short of the target, releasing the bomb at a computed point in the pull-up, giving time for the bomber to put some distance between itself and the nuclear explosion while the bomb 'tosses' onto the target. Always a risk of disorientation in the manoeuvre and I guess a
possibility that the a/c was pulling out of an unplanned steep dive on the northerly track having run in to the south. I think impact trail would be far more reliable than any eye-witnesses.