Character mistake: The officers count the inmates and say there's 10 missing. There are indeed 10 inmates hiding in the pool. However, Pennsatucky and Chang had escaped the prison. The officers counted Linda as an inmate, who had been hiding in Litchfield the whole season, and wasn't on the list. That would make it 11 people missing, not 10.
Character mistake: The zip tie handcuffs on the arrested inmates were not tightened. (00:25:18)
Answer: On the show, orange uniforms are worn by the new inmates, while the khaki is the longer-term population. Generally, there's no standardized meaning of the colors as every prison has their own color-coding system. For example, red could mark more dangerous inmates. Other colors could indicate lower-risk prisoners, ones with health issues, area designations, and so on.
raywest