The Court declined root cause analysis and published twelve unranked contributory factors. Drawn as a causal structure, three things appear that a list cannot express.
Causation runs vertically; accountability does not. Every path to the reef passes through decisions taken above the ship. The survey role was never operationally released. Force generation was never completed. Postings were made without the required proficiency. Charges were laid at one level only.
The equipment level acts upward. In a conventional AcciMap the bottom level is where consequences land. Here it is a source. The autopilot in speed mode turned an astern order into acceleration, and the absence of mode annunciation made the ship's state unreadable — to the bridge team in the moment, and to the investigators afterwards.
The densest cluster occupies four minutes. Between 18:14:47 and 18:18:23 the crew received a rejected command, an unremarked alarm, an accelerating ship under full astern, and a lookout's disconfirming report. Each was sufficient to break the diagnosis. None did.
AcciMap has no node type for the state of a mind. Salmon and colleagues note that its actor level represents flawed decisions without identifying what shaped them — situation awareness, operator mindset — and that it offers no taxonomy at any level.
So the magenta chain is accurate about what happened and silent about why a competent officer, holding a procedure he had been trained on, did not apply it. The Court was silent in the same place and filled the silence with a judgement: the officer of the watch should not have been distracted.
That silence is the residual layer. It is not covered by the design of the bridge, by the orders, by the training pipeline, or by the method used to investigate the loss.