Alsace Podmore was a powerful witch, but she was new to Azkaban and its prisoners. She had often heard the guards lamenting the loss of the Dementors, as their jobs had been that much easier when the prisoners were disabled by despair. Personally, she thought they were just a little lazy and wanted to get paid for doing nothing all day. Many of the other newer guards felt the same, particularly since the number had greatly increased with the departure of the Dementors, and had provided jobs for many who needed them.
Now, however, the lack of experienced guards was making itself known in the psyches of those left behind. Many were nervous about dealing with prisoners, and those like Alsace who weren't worried that it would give signals to the prisoners.
Her fears proved founded when one of the prisoners failed to follow the others back into the prison proper. She had yet to learn all the prisoners' names and thus wasn't certain which one this was, but his grey, straggly look did not bode well. She tried a solid, reasonable voice, but he refused to move.