Complex sentence: From this point the story becomes much darker, the students are sent to a non-aggressive defence school and forced to dispose of corpses they are then gassed in a shower chamber, dressed in full military attire (complete with collar).
Split into simpler sentences: From this point the story becomes much darker, the students are sent to a non-aggressive defence school and forced to dispose of corpses. They are then gassed in a shower chamber, dressed in full military attire (complete with collar).