Stanley Meyers Injectors seems to work similar to the water spark plug.
Maybe some little difference is, that Stanley Meyers injector plug, make no real spark. I think it was a high electrical field (which can bring a spark if you rise the voltage high enough).
Anyway, in both cases, the same will happen. First there will be a little electrolyses (central in the wfc or in the spark plug inside), then the spark or discharge do it like in ArcAtom welding. So the arc or discharge cause the H2 go to a state of H+H. And will recombine immediately out of the plasma zone. The O2 will form to O+O and will recombine to O3 (Ozon) or O2, etc....
So that is because a discharge like this can cause plasma state, that means nearly all moleculs or atoms in the "chamber" where the spark is hitting, are ionized. Normally moleculs connection break up and the single atom version will exist so long, as the plasma is "ON" or the atom is leaving the plasma zone.
So maybe Meyer generated a "soft plasma" without arcing. Heavy arcing is not good for material inside the spark plug.
We should not forget, that mayer didn´t only let water into the spark plug, but also some exhaust gases and already ionized air (Gas Processor). Therefor the result of the "explosion" in front of the "plasma spark plug" can vary. So it can be, that the VIC was was like a ignition coil in the video you posted. Bringing high voltage field to the chamber but without arc discharge.
Edit: IMHO was this the reason for the so called "Hydrogen Fracturing Process". So first splitting water to H2 and O2 and then destabilizing the H2 in the ignition tubes with the high voltage field.
During my water spark plug test, I made three important observatiosn:
1) The 200 to 300VDC (however) made permanent electrolyses in the spark gap of the spark plug creating H2 and O2. (same like meyer in the wfc, maybe with other voltages)
2) The high voltage of the ignition coil hits, ionize the created H2 and O2 gas and then the "explosion" vapourize the remaining water. (same like meyer in the gas resonant tube)
3) The explosion or arc creates ultra violett light arcs. When H2 is ionized and recombined, the recombination ends with a photon wave at around 400nm (UV).
That was the reason of the UV laser interaction to the H2 and O2 in the gas resonant cavity. The above reaction can also go in the inverted direction. UV hitting H2 will be ionized.