I agree, getting away from the problem's source is by far the best immediate approach. When people around you start coughing and pulling sweaters up over their faces at fumes you're not always sure where to go... this was strong stuff or it was magnified greatly by the environment.

We were just pulling away from the gate and moving back into the plane when you are considering whether or not to try and get off or ask for an EMT did not seem to be a smart move. If it had been mid-flight, we certainly would have done just that as quickly as possible after determining the source. I could have cared less about first and would have sat on the floor in the back.