The dog was blindsided by the cat, which resulted in an instinctive retreat. If the dog had seen the cat coming, things might not have worked out so well for our fuzzy hero (then again, a pissed-off cat can be a real handfull for most any dog, so who knows). Just glad that things turned out OK for mini-human and feline.
I did post a comment asking why mom checks on the boy and then takes off...seemed odd. Should have grabbed the kid and headed indoors, but she leaves the wounded and bleeding youngster to escape under his own power.