I can think of two explanations for the emergency release being outside the door. The in-universe explanation is that over-population made governments relax their safety code laws, in the hopes that horrible accidents kill off as many people as possible. That lack of safety laws carried over into construction of the base in the past, where the series takes place.
The other reason is that it's a plot hole, or a case of bad writing (or because the plot said so, or something else). In real life, there are a number of safety codes dealing with locked doors and the emergency release of said locks, for instance, these rules about fire exit safety. For the most part, this means that the door can be exited in one direction even if it's locked coming from the opposite direction. So, the scenario in question (getting trapped in the room) should never have happened. In a situation where it might happen (such as a door locking from both sides), if there were to be an emergency release, it would be on the inside of the room that the door provides access to, as opposed to the outside, otherwise, people could be trapped in a room. There might be cases where a manual release is required outside the door, as well, while still keeping the door secure from outsiders. In those cases, the release would likely contain a lock (likely, with a key that certain people have access to or know where it is). That way, people could access the room in an emergency, but the room would still be kept secure.
If, instead, it's a security door that practically anyone can access, then the question becomes "Why is there even a lock on the door?" In that case, the answer would be "bad design".
