I realise the inhibition of cytochrome c oxidase prevents the release of H+ ions into the intermembrane space, and that the ion gradient is required for ATP synthase action. However, I'm not sure how this causes cell death.
a) Prevent oxidation of Cytochrome C, preventing electron movement the cytochrome bc1 complex, which in turn prevents electron movement from earlier parts in the chain, shutting down the electron transport chain altogether? Thus, no ATP is produced and the cell dies due to lack of ATP.
b) Prevent oxidation of Cytochrome C, but not preventing oxidation in the other protein complexes*, merely reduce the number of H+ ions available for ATP synthase action, lowering the amount of ATP produced, and the cell dies due to low ATP levels.
I realise in either case, the ATP count is merely lowered, as ATP is produced by other methods, so my statement 'lack of ATP' is not totally explicit.
*This being the case, how are the released electrons dealt with by the cell? Are there electron acceptors to remove this?