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Its basically a trick of the meter and the way it samples the measurement. The part he is talking about with the diodes, is about the protection diodes that protect the circuit from the pulse from switching off the current to the coils of the motor.
The coil on a motor is essentually an inductor. An inductor stors current the same way a capacitor stores voltage. When you apply a voltage to it the current slowly increases until it either burns up or you max out the current due to resistance. However when you turn off the supply the inductor will spike the voltage to keep the current going, that spike tends to arc through things and burn them up. The diodes give a path for this stored current to flow without blowing out parts. It is short lived and is current that was originally supplied by the battery.
The best way to measure each side is with a scope that way you can see the voltage and current waveforms. Most modern scopes can even calculate power which will also appear as a waveform.
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