Originally Posted by Anno_Domini
Could be a plot hole, but not really.
For as we know, the other cop wasn't around Dent's room while there is at least one cop in Dent's room that is dead.
It probably falls into the “continuity error” category - a repeated detail that isn’t depicted consistently. A “plot hole” (imo) is a narrative mistake/omission that interferes with internal logic
. E.g.: “How could the hero start his car when he was shown losing his keys in the previous scene?” (Well, perhaps a sloppy writer didn’t notice the problem; or perhaps a sloppy editor deleted the explanation. In any case, it’s a plot hole.)
But in TDK
, nothing particularly crucial to the narrative depends on Gordon getting the body count exactly
right. So at worst… a continuity error.