Lupo getting pimp-slapped (instead of punched or kicked like the other thugs) by Liu every time he attempts to get up.
When he starts his raid on the police station, Liu fights his way past the lobby and barricades the door... which has led him into a room full of cops practicing self-defense. Both sides take brief pause at this twist of fate, before Liu very cautiously starts walking forward.
Towards the end, as Liu has gotten to the final level of the corrupt police station, he's facing off against a tough opponent in a cramped office area. They start waving at each other to Bring It, but both Liu and his opponent keep refusing each other's taunt, because they're both crouching in a perfect defensive spot and don't want to give those spots up.