I've had people seemingly intentionally move into my path. Absent any other data I would have to assume they were looking for a confrontation. That makes them the most dangerous animal on the planet (are they armed?). Avoidance is a very valid response.

And regarding good samaritan laws, my late father always lamented how physicians were usually not protected by them. As a physician he pointed out that responding to a cry for "is there a doctor in the house?" could end up with him losing everything he had.