1. There are no dumb questions.
2. Detcord would cut a channel about twice it's diameter on a wooden door. Normally, three to four strands are taped to a silhouette which is taped to the door and detonated, blowing a hole through the door and allowing access. A different method is using water impulse charges which are nothing more than 18" of detcord between two IV bags, placed at the top, bottom, and center of the door. This has the benefit of bending steel reinforced doors in a V-pattern and knocking them off of their hinges.
3. Anyone near the door would be injured, but not necessarily killed (unless they were actually in contact with the door). The guys detonating the detcord are usually within 6ft of the cord when it is ignited.
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