You are correct. That was what started the gas van system where they would put Jews and other minorities in the back with the exhaust pipe running back into the back compartment where they would die of carbon minoxide. This was shown to work but was abandoned as it would not reach the mass scale of genocide that Himmler and the rest intended to develop, which eventually of course led to the extermination camp system.
If you’re wondering about the comment I made about Himmler, I do not believe the moment restored his humanity by any means. I’m saying that it is possible that he did have an inkling of conscientiousness, however brief, that what he was doing was seriously wrong. But that is merely speculative and food for thought perhaps…