That was his pay for overtime. I don't think they were paying him time-and-a-half, in fact I think they probably paid him less for the overtime. So I'm guessing he made more than $2/hr for most of that 10 days.
and if that's for 7 days a week 10 hours a day as the reporter said, that's 300 hours.. so 1.33 dollars per hour.
BTW, the typical salary range for a junior Ruby dev in a second or third tier city in China is about 800 - 1600 USD per month. Just to put things in perspectives
But they work a lot more hours.