What a great story. My uncle was also a part of that break out force that made it to the Yalu River. He told me that while his unit was waving at the Chinese across the river, the counter attack had started down the way a bit. He with his Garand (he told me he hated the carbine) ran all the way back to the starting point. He mentioned that most of the Chinese soldiers he shot at were hopped up on something because they just kept on coming.
My brother-in-law was there when the Chinese invaded. He said he saw hordes coming at them in waves. China had so many young men this was a way for population control as those in front had rifles, those behind them had spears and clubs, those behind them had nothing and were expected to pick up the rifles of those slain.
[sidebar I]: I can't remember if it was an Army or Marine guy who told me this. The Chinese used bugles instead of radios in some of their attacks. In one particularly hairy "human sea" charge they were about to be overrun when one of the guys, an ex-musician, took out a captured Chinese bugle and played "Retreat!". The Chinese started to mill around in a WTF moment, which allowed the Yanks to call in the artillery and break up the attack.
[sidebar II]: Apropos the above, one of our ordnance guys asked a captured German why they had machine guns with such high cyclic rates compared to ours. The German said "You've never faced a Russian "human wave" attack, have you?"
Somehow, he managed to survive and crawl back to American lines, and later became a senior NCO and MP. But seeing all his buddies slaughtered by the ChiComs during their counterattack deeply affected him for the rest of his life.
And he too thought that the ChiCom soldiers were hopped up on some drug, since they just did not want go down.