"i want to die by falling on pluto with platinum space ship that menaces with spikes of gold and thermonuclear mustard biscuits"
Give them a miniature model of their fancy spaceship and their biscuits, then put them on a basic autopiloted ship heading to Pluto. If they try overriding the autopilot they'll just strand themselves in space.
"i want to die in a black hole"
Drop them off near the event horizon.
"i want to die in the dining hall by exploding to millions of pieces"
Build a basic dining hall out in the middle of a Martian desert, then blow it up.
"i want to die from booze"
Submerge their head in a bucket of it for the necessary amount of time.
"i want to die on a planet that is billion kilometres away from here"
Stick them in a stasis tube, put them on a basic autopiloted ship, then send them on their way. If they don't make it, it's the fault of their own planning.
"i want to die from drug addiction"
Krokodil.
"i want to die from very low doses of cyanide in the nuclear powerplant control room"
A very large amount of very low doses. Just keep some people in there to make sure they don't mess with anything.
"i want to die from high doses of radiation in the public dining hall"
Build a basic dining hall, name it "The Public Dining Hall", stick them in it, fill it with radiation and seal it.
"i want to die on a nuke that is falling on earth"
Threatens the lives of people other than themselves. Not allowed.
"i want to get killed by the president while his children are watching"
I would be honored, though I have no biological children. I could always adopt some bug larvae or something and raise them as my own, though.
"i want to die in the presidents bed with his wife from low doses of booze intoxication"
I don't really think you can die from getting buzzed, so that wouldn't be allowed either.
It's perfectly fine if the prisoners want to get clever, because it is most certainly a game that two can play.