Historically, the FAI in the Spanish Revolution operated "humane" concentration camps where guards and prisoners intermingled and the prisoners didn't really have a need to escape. I suspect they didn't escape because living in the anarchist concentration camp was better than dying for Franco as Franco's army was composed of more mercenaries than fascists.
This is not the place to discuss the merits and demerits of historical anarchist concentration camps. What about current wars? Rojava maintains prisoner camps for Daesh (ISIS) prisoners who do try to escape and rejoin Daesh.
What do we do with these prisoners of war if we operate under an abolitionist framework? Drug users we treat medically. Abusers we rehabilitate and reconcile. Antisocials we accommodate and help them improve themselves. Rapists and murderers we eject from the community or even exile. But what if there's a war going on? What do we do with the prisoners of war? What if they're not like the Franco soldiers who don't really have an urge to escape? What if they're the fascist or terrorist kind like the Daesh who do want to escape to conquer and enslave?