For large enough astrophysical objects, internal pressures are insufficient to prevent gravitational collapse to sizes smaller than a critical radius where the magnitude of escape velocity is equal to the speed of light. In coordinates natural for distant observers the collapse time diverges as the critical radius is approached. On the other hand quantum evaporation as witnessed by stationary observers is traditionally modelled to take place in finite coordinate time. In this work the coordinate invariant temporal order of non-spacelike separated events in the vacuum exterior manifold and the behaviour of inbound null trajectories are examined. Based purely on descriptions of conformal diagrams and two well-known sets of coordinates, a major inconsistency in the traditional model of an evaporating black hole is exposed.