I suspect it was like the story a Russian friend told me of her uncle in WW2. When Stalingrad was under siege, the Soviets went into the prisons and gave the prisoners the choice of 1) being shot; or 2) running in front of the Russian lines to draw sniper fire so the Rus Army could locate the German snipers and hit them. He took the latter option, was hit several times, but survived.
In this case Wagner PMC recruited Russian prisoners with the promise of commuted sentences if they fought honorably and survived on the battlefield for one year.
One year of fighting vs nine years of hard labor in a Russian prison...which posed a greater risk to an African drug smuggler?
Russians also used their prisoners to clear mine fields by walking over them.