Turbine Ventilator, make a 10'' hole thought the room celling and run the scrubber in the crawl space, then out thought the turbine. parts and mats maybe $100 bucks if you have the 10'' hole saw already. maybe even install a booster fan under the turbine. once your in the crawl space you will have a ton of options really. you can use as much ducting as you want, if you want to just run it to the passive roof attic vents.
this is extreme, I am thinking you cant even walk around the tent right?