7-52-2-1-3
Reflex attack reactions are only performed if the Chasing unit is fast enough, etc...
My wife's Slaughterers (only Srok, the rest couldn't dent the shellfish) got a crazy crit and knocked a Crabspear prone via Glass Jaw, sending the remaining Crab fleeing due to low Wild reaction to panic. Her unit opts to Stand rather than Chase, which is an easy decision for a Weary unit. But why don't they get a Reflex Attack Reaction against the fleeing unit?
In contrast, chapter 7-20 makes it seem like a Reflex attack reaction is performed any time an enemy unit is fleeing from combat. The first paragraph says they "often occur as a result of an enemy Fleeing or Withdrawing from combat". But it is not mentioned as part of a Stand reaction.
It seems even more strange to me because the rules for a voluntary Retreat action are very clear: If a Retreat test is passed, the unit fends of their attackers and beats an orderly retreat; if the test is failed, the engaged enemies get to make a Reflex Attack reaction on them which may cause them to panic. I would think that a unit that is starting to panic already would be much worse at fending off any attacks of opportunity than voluntary retreaters!
I also wanted to clarify the rules in 3-8-5 and 7-52-5 because we left off our battle tonight when the Crabspear fled point-blank into a giant Kadamastar! If a unit flees into an enemy unit, rule 7-52-5 refers the reader to the Moving Through Units section 3-8-5, which states that the fleeing unit becomes a Moving Through unit if the mass is at least double that of every warrior in the path. (It also confusingly states that 'some units will involuntarily move through intervening units, even friendly ones, and its warriors can be of any mass to do so.) There is a section on Impact Strikes and Reaction Strikes that explains what happens next and then a part that tells how the unit moved through gets displaced.
What I DON'T see in either the Fleeing Through or Moving Through section is what happens when a Mass 7 Crabspear slams headlong into a Mass 16 Kadamastar! Are there still impact strikes? If it was a fleeing Vras in this situation, would they get terrified and panic in another direction? The rules are silent to these points unless I'm missing something and there are not helpful signposts.
The only thing I could find is part of of the Moving Through rules, which seems to be addressing a slightly different situation where a fleeing unit runs PAST an enemy unit:
3-8-5-4
Even if he is not a Moving Through warrior, should any part of a warrior's base Move Through an enemy warrior's attack range [...] that enemy warrior must perform a compulsory Reflex Attack action
Finally, the rules seem to be silent about engagement at the end of the sequence. If the Crabspear could move through a smaller mass unit, it would end up involuntarily engaged per section 3-8-5-3 but I don't see a similar section that addresses this other type of possible involuntary engagement!
Is there a section I'm missing somehow? I feel like much confusion could be avoided if the fleeing section had a 'Fleeing Through' section that points to the 'Moving Through' section and a 'Fleeing Into' section that states what happens when a fleeing unit 'Crashes Into' a unit of larger massed warriors! After all, the Moving Through section can apply to voluntary movement as well. Crashing Into would be a quite distinct event that can only happen during compulsory movement. After all, voluntary movement into an enemy unit is an Engagement or Charge, and this is different. (I DID check the Engagement section and while the words 'involuntary Engagement' appear, they don't seem to mention it as a result of fleeing)