Sylvia. Probably the least sympathetic of the guards to begin with, but she gets a few Tear Jerkers. Her first husband commits suicide due to financial pressure and her second tries to murder her for money.
Many of the jerkass characters have Woobie moments at some time in the series; Denny Blood, Shell Dockley, Buki Lester, Maxi Purvis, Snowball Merriman, Di Barker and Al Mackenzie being the most obvious examples.
Nightmare Fuel: When Yvonne gets trapped in the hanging cell and left to die.