Trivia: Of all the different Stephen King adaptations, this one bears the least resemblance to its source material (not counting The Lawnmower Man which King demanded his name be taken off).
Trivia: When Killian is talking about the next possible contestant, he points out he's 120 pounds and wouldn't last 30 seconds. This is somewhat making fun of how they used Arnold Schwarzenegger to portray Ben Richards. In the book "The Running Man" (which has a very different structure), Ben Richards is described as "scrawny", the complete opposite of Arnold.
Trivia: Ben says to Killian "I'll be back", his famous line from The Terminator.
Answer: When Ben is walking to the apartment door, he has a huge case with him which is big enough to hold clothes and even shaving equipment. Ben entered the door code into the keypad which unlocked the door so the code was never changed.