If the story is correct that the female deputy was in the room alone with the perp while he was changing clothes--that is strange.
She was allegedly in the room to remove his cuffs so he could dress.
She wasn't in the room while he was changing as he got her and shot her prior to that or after.
Where did you hear she was in his cell while he was changing.
It is strange. We always had two officers when transporting an inmate. On outside transports, two officers were required. One carried, the other didn't. Usually the officer driving the vehicle didn't carry the weapon. Inmates were always fully restrained: handcuffs, leg irons, waist chain, padlocked blackbox to keep cuffed hands in rigid position. If the inmate was male, at least one of the transporting officers HAD to be a male. I'm a female and worked 23+ years in all-male facilities in the NYS prison system...uniformed staff, first as an officer and then as a Sergeant for last 13 years of my career.