Okay, let’s get cute with it then.
-=(blue)The most important detail in how the doors were circumvented was the “presses” mentioned in the first paragraph of the board. They could be programmed like 3D printers, and used to create arbitrary objects out of metal, which would be caught by the elevator metal detectors…or plastic, which wouldn’t.
The culprit really is Meridies. During a previous experiment cycle, she stole Septentrio’s emergency key using the maintenance blind spot I established earlier. She replaced it with a visual duplicate (say just some random key of the same size) while she had his original, but only kept the original until she had the opportunity to use one of the presses to print a plastic duplicate. After that, she returned it. At the start of this experiment, she had that plastic duplicate key on her. Given the red about there being no portable objects “in the control rooms,” and no suspicious non-research-related items existing in the facility, I’ll say she used one of the “machine parts” created by the presses—made of plastic, of course— to jam the doors. She took the part down to the control room via the S elevator at 10:00:26, and stored it in there for only the next hour or so, returning it to the atrium after the alarm was triggered.
The actual murder played out largely as I described it in my last post, except with Meridies as the one doing the sprinting through gaps. She wasn’t able to control the N wall directly (i assume so, at least) so she got it into place through a series of swaps, which she was able to perform on a time-delay thanks to the lab’s advanced equipment. Say she first swapped S with W, leaving W on the S side. During this swap, she exited her own control room through the gap between the two (unlocking it for log entry 1). Then, her second queued-up swap took place, switching S with N. She ran through the gap again, carrying her plastic machine part with her.
After entering the W control room (log entry 2), she choked out Occidens, dragged her out the door after pressing the button (propping it open with her machine part along the way), and into the testing room where the S wall (on the N side of the room) had been magnetized. The magnetic force of the wall jammed Occidens’ headset, and she was pulled onto it and immobilized automatically, giving Meridies the opportunity to quickly duck back into Occidens’ room through the propped-open door and avoid interference of her own. Because the door was propped open, she could know when Occidens was dead, which was when she told the group to stop at 10:59:26. Her protests to stop the experiment earlier were misdirection: she knew the other two were single minded enough to ignore her, so she pretended to be concerned.
After that, she performed a series of swaps in which she escaped through the propped-open N wall (removing the machine part to return it to her room), entered her room again through the gap between walls mid-move, and swapped all the walls back to their original position. Finally, she turned off the magnetic force on her wall too late, dumping the body next to her own door.
Her motive in all of this was some kind of jealousy or professional disagreement towards her subordinate, Occidens. She tried to frame Septentrio through use of the N panel as well as her duplicate key, but thanks to her mistake, he and the internal investigators were able to see through it.=-