Ah but this was pre-systemd so you would have been screwing around trying to find whatever script was being used to lock the doors after close of business.
Well it's IRIX, so you'd just create a little bourne shell script in /etc/init.d, with symlinks from e.g. /etc/rc2.d to start/kill it on the respective run levels.
This was a pretty critical system though so why not just place this particular program inside /etc/inittab ?
Well, we are talking about managing critical infrastructure on a theme park riddled with dinosaurs. Potentially the definition of working under pressure.
I wouldn't think even teenage Kevin Mitnick on Mountain Dew can himself bypass the terminal security (if any), prompt his way to the safety mechanisms, and override their behavior. All while being assailed by a velociraptor.
pretty simple explanation: the girl in the movie is more talented than teenage kevin mitnick. if that's a bridge too far for you, i'd recommend not watching the rest of the movie because it's about people cloning dinosaurs using frog DNA.