The ironic thing is this phenomenon is in fact part of our survival system, and meant to keep us alive by putting our system on "red alert" when we are in a threatening situation. It is just that; it works better in some cases than others, better with some sorts of threats than with others. Back in an age when a more typical threat was a cave bear, it was a useful thing to have one's warning system go off at a particular sound or smell or location--surviving a first run-in with a momma bear protecting her cubs might leave you with neurological "reflexes" that would help you to avoid a subsequent encounter. It's not a bad thing if one avoids all contact with such a creature.
But what happens when an officer's warning system is triggered by a particular location, or kind of call? You can't just avoid it; and sometimes your reaction goes beyond the reasonable alertness and caution that is necessary for officer safety into something closer to a state of panic. Anything that interferes with your accuracy in "reading" a situation is not your friend!
Well, these things can be dealt with. If they don't work themselves out with time, there are also very effective therapies for desensitization available these days, for example, Eye Movement Desensitization and Reprogramming (EMDR).