I guess Doze could 'mistake' the two
and saw the DUN/'shell' as needing service, which it provided, at least part of it..
The real oddity to me seems - that the HD wound down but.. not during a real shutdown. That this was an 'incomplete' shutdown is implied by the fact that the Power button did not immediately restart.
See what I mean? Even a BSOD doesn't (usually) initiate seppuku :(