I could write that screenplay because when I was growing up, my father cared enough about me to give me specific, hands-on instruction on how to deal with bullies.
None of it applies today, because his methods, meeting the force of the bully with superior force caused by quality pain, is not allowed now. Kids being bullied are somehow supposed to call for a truce or time-out and let adults settle the situation.
Well, Pilgrim, real life doesn't work that way.
My father wasn't a big guy, only 5'4", and as a practicing Jew in the early Portland public school system, he probably got picked on some. Remember, at that time, there were zero "hate" laws, and even though his parents had fled the Tsar's "pogroms" in Russia, most Americans didn't know or didn't care about anti-semitism.
My father WAS an athletic guy, though, and he was a decent gymnast, specializing in the rings, which requires huge upper-body strength and control.
As I grew up, it was obvious that I didn't have my father's upper-body strength nor would I ever. No problem, he showed me some defensive moves I can still use today, as I approach the age of 70.
The primary defense against being grabbed from behind is to immediately tuck your chin into your chest, so your assailant doesn't get an arm under your chin and around your neck to choke you out. You then have two choices: twist out of the hold you are in by pulling down on the assailant's wrist and pushing up on his elbow while ducking under the hold, or you apply immediate counter-pain.
The counter-pain is applied with a technique called shin-rake. If the larger bully lifts you off the ground, it is even more effective. You raise your knees into a tuck, and extend the feet outward (like you would do on the rings), and then swing the legs down so that your heels make contact with the bully's shins, violently. You then maneuver your upper body so that the bully starts to lose control over his hold, and keeping your heels in contact with the shins, rake downwards. The human shins are the place where a major bone is very close to the surface, so the flesh is shredded between the edges of your shoes/boots and the bully's own leg-bones. Great pain is caused, and if your technique is perfect, a lot of skin damage as well.
What if the bully doesn't lift you off the ground, but merely holds you in a bear hug from behind? Reacting to this rear-grab is even easier. The bully will have at least one of his feet exposed to a foot-stamp. The top of the human foot contains more bones in a small space than any other place, except maybe the hands. It takes very little force landing directly on top of that foot to break some of those bones, and breaking even the smallest of them will cause huge pain. The technique is simple. You look to see where the bully's foot is (this should be easy because you have ducked your head and are keeping it ducked), you raise the appropriate leg about a foot, and stamp down on the bully's foot. If you miss high, you will likely effect a shin-rake, as in above, and if you almost miss low, you should get at least the toes. When the bully feels the pain in the top of his foot, he is going to let you go. Flight or continue the fight is then your choice, but now you have a bully who can't stand properly, pursue, or move quickly side-to-side. You should then be able to get in some telling blows, kicks to the groin, whatever would be your winning technique.
I had two occasions to use anti-bully techniques. One was in the English boy's school I went to in 1954 when my Dad was stationed in London. There, the classic school bully picked on me, both because I was small and because I was a "Yank". It came to blows, but because the English educational system still had it's head screwed on properly then, I did not get punished for fighting the bully, but I was invited to continue the fight in the boxing ring! I lost to him in the boxing ring, going the full three rounds, since he had me in reach by 6" and weight by 40#, but we respected each other afterwards and there was little bullying from him again.
The second time happened about 10 years later. My little brother (now dead) was in High School, and I was going to night school college classes, so I usually picked him up at the school and we both went home, me to study and he to do whatever. As I parked in the usual place, I noted a throng of kids in a tight knot on the sidewalk. As I walked towards it, I noted my brother was in there, fighting a much larger guy. My brother was 4" taller than I, and this guy had to be 6'5" at least. My brother was taking some pretty good blows, but in his style, he was laughing them off and talking trash. I saw that the fight wasn't going to end without him getting beaten down, so I stepped up behind the bully, and tapped him on the shoulder, and when he turned, I gave him my best shot to the jaw, almost breaking my hand. The blow had little effect except to make him stop beating on my brother. He concentrated on me. The guy had close to a foot of reach and at least 100 pounds on me, and even with my guard up, I knew I wasn't going to last long, the blows I was taking on just my forearms were killers. He dropped his guard just for a moment, though, and I put everything I had into one shot to his nose, which easily broke. Two forceful streams of blood started, and the big lug used both his hands to grab his own face, and sat down on the pavement. My brother and I left. My brother told me when we got home that I had run 5 stoplights, but I didn't crash. I was that pumped. My brother then told me I had just beaten the school's heavy-weight wrestling star (who later went on to become State champ). I told my brother he needed to pick on some lesser opponents. It turned out that my brother's own trash-talking to this guy had egged him over the edge. I would have been doing my brother a favor to let him take the whipping, but blood is thicker than water.
Lesson here: few, except maybe hockey players who get many broken noses, can stand up to one when it happens to them. Another very vulnerable part of the body, yes.
Not much point in this reminiscense though, since we aren't supposed to fight to defend ourselves or our family members anymore.
Oh, well.