Great story. You went into Kickass Mode.

I had a very similar experience once myself. When I was a student, I was going out one night, and on my way out, as I was wont to do in those days, I smoked a joint. There was a dog barking very loudly from my neighbor's yard across the alley.
I paid no attention to it. The dogs were always barking.

I hopped into my car and as I spun the car out of my driveway, my headlights illuminated my neighbors's yard and I saw a terrible sight. My neighbor's big husky had tunneled under the chain link fence around his yard and under the hedge of ligustrums growing on the other side of it. The dog was under the hedge, all tangled up in his leash, and his choke collar was strangling him. Another husky was unleashed and doing all the barking, and he was really pissed.

I parked my car so the headlights would light up what I was doing, let myself in through the gate, and whipped out my sheath knife to try to cut the dog free. At that moment, the other dog was going into hysterics, but this eerie calm came over me, I just stared him down
and he backed away, he knew something was very wrong, and it was going to take a human to straighten out the mess, so he backed off just out of reach, but continued barking, growling, baring his teeth and acting in a very menacing manner. For my part, I was determined that this dog was not going to die if I could do anything to stop it, and if his pal didn't like it he was going to just have to wait his turn.

It took me about 5 or 10 minutes to crawl into the hole the dog dug, under the fence and the hedge, and operating mostly by feel, follow the lead around a million branches and roots until it disappeared deep in the dog's fur. The chain was so tight I couldn't get my finger under it, and it was almost out of my reach, with my arms extended. I finally managed to cut the lead and dragged the unconscious beast into the yard (these were very big huskys, like wolves, maybe 60 lbs?)

By this time I was exhausted, and after I loosened the chain I actually collapsed on top of the dog. The other animal finally quieted down as if he sensed everything was under control. The dog I had rescued finally came to,
and began to lick my hand.

At that moment, the redneck who lived in the house next door, the jerk who owned the dogs, came out, and said in a drunken voice, "What the hail you doing in ma yard?"