The position of the Chinese prisoner's right hand changes from closeup to non-closeup during the grenade/serenade scene. He's trying to get at Hawkeye during the closeups but Hawkeye is holding the guy's hand down on the other shots.
The Chinese soldier with the grenade speaks Japanese.
While everyone looks for the pin or a way to sedate him, nobody helps Hawkeye get the grenade hold onto or out of the Chinese soldiers hand. Funny a hospital has no syringes either.
After surgery, all the surgeons go directly to the officers' club while still in surgical scrubs, bringing the blood and germs with them.