RE: What would you do?
I had a similar experience
I was flying my extra 230 (old EZ ARF) and a beginner and his instructor start taxing out, I did my take a step back, gain a little altitude, and make sure he gets off the ground ok, I hear the motor rev up and look over and see it rolling right down the stripe, so I figure all is well and look back to my plane, all the sudden the engine is getting louder and when I look it's WOT, 30' away from me chest high and headed right for me,,, I drop to the ground, dropping my Tx, the plane crashes 10' directly behind me,, while laying on the ground I reach over and pick up my Tx and save my plane from crashing.
Close calls suck, But luckily my preliminary instinct to gain a little altitude saved my plane,, when I went to the ground, I could care less about anything but saving my skin