Doesn't seem completely unreasonable the way it is. Someone truly *panicked* isn't exactly in a reasonable state of mind. Consider all of the times when large groups panic and trample people.
The problem is that dwarves don't currently seem to have a state of mind between calm and panicked. Until they do, I think that it would make sense for them to flee to a meeting area or designated burrow, since most things that scare them aren't really particularly dangerous, even though many are.
The optimal solution, however, would be to have multiple levels of fear; there needn't be many, just two should suffice. An "afraid" fear level, in which they would flee toward the nearest meeting area and/or a specially designated burrow, and a "Panicked" fear level, wherein they would respond as they do currently. Whether they become Afraid or Panicked could be dependent on a combination of the stats of the creature that frightened them (either via the implementation of a new [SCARINESS_LEVEL:] creature tag or some kind of mathematical derivation of the creature's other tags), combined with the Dwarf's personality traits (and in particular, one or more of the following personality traits (in descending order of potential relevance): ANXIETY, VULNERABILITY, SELF_DISCIPLINE, SELF_EFFICACY, EXCITEMENT_SEEKING, and CAUTION)