Look, there are a lot of people on here with a great deal of smarts and expertise. All the lights suggested are great lights, no doubt. However, this light will fill one highly specialized need....That of a Corrections Officer. I know I'm new here, so let me help to explain what he needs it for. Then, maybe everyone can collectively come up with a better light than me.
A Corrections Officer (CO1 or CO2) is, for all intents and purposes, in prison for 8 to 12 hours a day. We basically live with inmates for 8 to 12 hours a day. These are real people with families and friends who come to visit. They're not monsters (some are, to be sure). For your safety, the safety of others, and on the basis of good morals and ethics, the CO1 needs to treat every inmate with respect. 16 hours a day most inmates are allowed to roam freely within the confines of their respective blocks. They have keys to their cells, and the ability to congregate freely during those times. It's not like the movies where they are locked in a cell with a cell door made out of bars. It's a door with a 3X18 inch window we can look into. That light will be used ALOT to toss an inmates cell looking for contraband, so a bright o'l hotspot will just help to mask contraband behind an eye-burning hotspot at less than 3 feet.
Now, let's say this guy works at a level 5 penitentiary. That's maximum security, with murderers, rapists, and the worst of the worst. Most will never get out, and have nothing better to do than spend all day thinking of ways to get back at the "cops" and the CO2 will fit that bill nicely. So the OP needs to treat them all like men, and try not to **** anyone off. That leads me to my suggestion of the Malkoff M60W MC-E.
The OP can't just shine a light in an inmate's eyes that has a hot spot soo bright that it burns retinas. That's just going to upset the inmate, and all 50 of his Arian Brotherhood friends! He needs a light, like he said, that is pure flood. No hotspot at all. For the confines of a prison, there is no need for throw any further than 140 feet. We have spotlights for the yard and the bug zapper fences. And at as close to 400 lumens as possible, he is now limited to an MC-E or a P7 in a host that can handle 2 or 3 18650's.
My suggesting is for the Malkoff M60Warm MC-E dropin. It's been sold out for a while but can be special ordered my calling Gene Malkoff. Then get a Fivemega 2x18650 or Leef 2x18650 from lighthound.com, some AW 18650 batteries and a charger. Get an extension tube to stretch it to 3 18650's if you want, but I would imagine that the 2x18650 will get the job done. Just keep the extention tube tucked away in the control pod.
SO there it is guys, those are some of the reasons why he needs a pure flood light with 2 or 3 18650 capability.