About Transit in Beijing

I will be arriving at Beijing at 10pm on Oct 2nd and departing Beijing to Singapore on Oct 6th 1 am flight. Since my flight is on early a.m, I am 3 hours past my 72 hour limit. By the time I leave the airport on Oct 2nd and back to the airport on Oct 5th, i should be within 72 hours. Will this be fine? please advice