Complex sentence: Hoffman's tape urges Strahm to enter the box, but he stops it short and ambushes Hoffman, sealing him in the box after a brief struggle, and causing the room's door to seal itself.
Split into simpler sentences: Hoffman's tape urges Strahm to enter the box, but he stops it short and ambushes Hoffman. After a brief struggle, he seals him in the box, causing the room's door to seal itself.