Orthodox Holocaust historians tell us that in the Nazi death camps there were units called Sonderkommando. They were made up of Jewish prisoners who helped the Germans murder Jews. We have much witness testimony from these Sonderkommando survivors as to how the alleged homicidal gas chambers worked. In fact, witness testimonies are the only insight to how the gassing procedure worked as any German documents relating to the alleged gas chambers are said to have been destroyed by the Nazis. Today the Sonderkommando survivors are praised and spoken of in a positive light despite the fact they were accessories to murder.
Dario Gabbai is one such Sonderkommando survivor. In this interview Gabbai says that 15 to 20 minutes after the gassing they would open the door and start the process of moving the bodies. He also said there was only room for standing and that makes sense given the size of the alleged gas chambers.

We also have this account from ex Sonderkommando, Filip Müller. His version is unique because the victims are still dressed, creating the extra work of removing the clothing from thousands of dead bodies. Müller does not give us an exact time from the gassing to the clearing out of bodies, only that it had been a short while and that the bodies were still warm.
In Müller’s version of events there was more than room for just standing.
And we know that Müller was not wearing a gas mask because of this incident with some poppyseed cake.
Here we have testimony given at the Nuremberg trials. It is not from a Sonderkommando, as none of the former Sonderkommandos were summoned to Nuremberg for some reason, but from Marie-Claude Vaillant-Couturier, a former inmate at Auschwitz. At least the people in her story had the sense to wear a gas mask.

Now, if you’ll turn your attention to the chart below you’ll see the point I’m getting at. As you can see it takes hours, not minutes for the deadly hydrogen cyanide to fully evaporate. Note that this chart is for a low humidity setting with fine distribution. In the setting of a gas chamber, which was in an unheated cellar packed with bodies, the humidity would have been high. High humidity further delays the evaporation of hydrogen cyanide (see page 237 for the explanation of this). This means that according to the official narrative, and the claims of the Sonderkommando, deadly gas would have still been emitting from the Zyklon B pellets when the Sonderkommando opened the door and started clearing the chamber.
For a detailed explanation of the evaporation characteristics of Zyklon B see pages 236-240 of The Chemistry of Auschwitz—The Technology and Toxicology of Zyklon B and the Gas Chambers – A Crime-Scene Investigation.
What about those wearing gas masks? Without a hazmat suit the gas masks wouldn’t have protected the men entering a chamber that had deadly gas actively being released from pellets. Hydrogen cyanide readily dissolves on moist surfaces and can be absorbed through the skin. We have a real life example to illustrate this (see my article, Gas Chamber PPE, for more information about this topic):
Even if we step over the inconsistencies of these witness testimonies we can clearly see that what they said happened couldn’t have happened. And the issue of entering the alleged gas chambers too soon after the alleged gassings isn’t the only impossibility that has been attested to. Read this article for some more troublesome testimony.