1. The place is a correction facility.
2. Walter is a warden
3. Johnny is a murder convict

It is creative, how you manage to bring me through to the end, before i can figure out the plot, all of which becomes clear only on looking back!!

Meanwhile the clues are actually there in plain sight!!
a) strict rules
b) roof over your head, three meals a day for free, book to read...Overall, prison amenities...
c) Desire for freedom!
d) and the final clue - murderer, and for all its worth, the prison gates...in the caption!!!

It is a creative and revealing story. I credit you.