As with the 'Teleporter trap' video (https://youtu.be/_V2rpfrurxk ) this shows one of the places where a player might accidentally become trapped, unable to proceed except by loading a previous save-game, restarting the level, or using cheat codes (in Doom II versions that allow it).
Here the player triggers a rare crushing-floor trap and gets permanently stuck. (This specific example would've been fatal without acquiring the armor first.)
Notes on the making of this video: In order to save a couple seconds, I use the edge-activation exploit on a switch in the big room by the level's entry point.
Doom II: Hell on Earth Statistics For Classic DOOM
At this time, Classic DOOM has 1,450,388 views for Doom II: Hell on Earth spread across 248 videos. There's close to 6 hours worth of content for Doom II: Hell on Earth published on his channel, roughly 50.07% of the content that Classic DOOM has uploaded to YouTube.