Usually there was music playing on the side of the pit where the large quantity of dirt was in the form of a mound obscuring view of the actual executions. The victims were initially brought to this location and forced to undress(sometimes not) and wait while typically small groups were brought around to the actual pit. It is important to note that this form of execution was not widespread due to troop morale issues with executing women and children. The gas vans utilizing redirected exhaust and early carbon monoxide chambers were tested as a grizzly solution to this issue years before the mass executions at camps such as Auschwitz started. Early in the war before the Wansee Conference and during the late war periods in desperation from the impending loss of the war were when these forms of execution were predominately taking place. This is the late period when the Nazis attempted to cover their tracks and exhumed the corpses with the intent of burning the evidence. The victims were brought around to the other side of the pit in small numbers typically and while kneeling near the edge or in the pits were shot in the nape of the neck with a pistol/rifle or they were machine gunned enmasse pending. In the cases of the sondercommandos executed they were so psychologically destroyed they had no feelings on being shot in this manner either at the camps or pits. Of course this was not always the case and there were several uprisings from the sondercommandos at death camps with some being relatively successful, one being Sobibor. Completely horrible and completely atrocious. Sick, twisted and deranged is the only explanation for the mentality of a man wishing to enact this procedure. Pathetic is the man believing orders validates these actions. I don't believe I need to answer the heart of your question. It is fairly obvious what happened once they were in the pit.