Timed Gate

The timed element makes the threat one of lost time rather than lost progress. It forces the player to act and think quickly instead of taking their time with their movements like in the previous challenges. Additionally, this element of necessary speed can cause more panic and fear in the player than being chased by an easily avoidable boulder can. I would make adjustments to how long the door is open based on length of path to the door and how easy it is to traverse that path, judged by myself and, if I have time, playtesters. Timing-based challenges can avoid feeling unfair by making sure that there are no unseemly tricks or traps, and by ensuring that the controls and game feel are tight enough to allow for precision movement (which the base we are working off of does not have, I must lament).