As of Alpha-10, emergency personnel that are available are Firefighters, Paramedics and Riot Police.
All emergency personnel cost $100 to purchase and can be controlled by the player. They will come in personalized vehicles fitting to their job, a good idea is to have the vehicle reach the end to get the units inside the prison faster. All emergency personnel can be hired any time.
Firefighters: Can be called to fight fires in your prison if there are any. They come in 4 units per purchase and to use them you must hold down "H" while having them selected and point where you want their hose to fire. You can call in 2 firefighters max.
Riot Police: Can be called at any time to the prison. They are usually used to fight riots. Riot Police are stronger than normal guards, but can still be killed or injured. Having riot police on site will increase the danger level of your prison. They come in 6 units per purchase and will fight prisoners who are doing misconduct. You can call in 3 units max.
Paramedics: Are just like doctors and come in 4 units per purchase, 2 max. They will heal any guard or prisoner not fighting. A good strategy would be to control the whole group of 4 paramedics into a large group of injured prisoners and/or guards to be more efficient.
In Alpha-7 the developers added a Lockdown mode. When activated it locks all jail doors until you deactivate the Lockdown mode. They also renamed the old Lockdown to "Bang Up" which makes all willing prisoners move back to their cells. Useful during riots (or when you're expecting a riot) to prevent non-rioting prisoners getting caught up in a fight or feeling like rioting. Having your prisoners "locked up for no good reason" increases the danger meter.