How about this idea:
I collect my bags and leave them at a baggage store facility (there are 2 in IAH) then pass security using my mobile BA boarding pass. Then after spending 3 hours in AmEx Centurion lounge (I can enter it early since I'm a connecting passenger) I exit the terminal, get my bags, drop off my bags to BA counter and go through security again. Will that work? Can I pass security twice using the same boarding pass?