I have a 1 p.m. intl departure out of PEK T2 on a Saturday in September. I am wondering whether it is advisable to visit the Great Wall (Mutianyu section) before the flight. Rough plan would be to hire a private driver to do this:

06:30 departure from hotel in Wangfujing
08:00 arrive Mutianyu when they open
2h - 2h30m at GW
10:30 drive to PEK T2, arrive before noon

Is this doable? Or is the 2 hours at the GW just too short, or the drive to PEK T2 too risky? This is a flight I can't miss. If this is a bad idea I would just visit the GW on another day.