Seems to me that if an engine is an "air pump", and the exit was blocked, how would you get more in then? If there is no where to go (pressures being equal) then additional air would not go in. The cylinders would stay filled with pressurized gas (which would equalize as the pistons travel down) but not accept any more when it reached BDC. And since the gas would contain very little oxygen, combustion would not be supported. If there is no combustion, then there would be no additional pressure on the piston. Then rpms would be extremely limited even though the operator would continue to open the throttle. However, nothing would happen.
So my question would be did the engine go fast prior to the noise? If it did, then it was not the FAE.