Slitherine

We were playing a game of FoG last night. A Heavy Foot Battle Group routed into a vineyard near the rear table edge. Vineyards are difficult terrain limiting movement to 1 MU per turn. I can't find anything in the rules that says Routing units ignore terrain. The net result is that the routing unit was given many more turns to rally than it otherwise would get because of the very slow movement rate. Am I right? If the answer is yes this seems a bit bizarre to me. I can see how terrain effects troops trying the maintain order and formation but how would terrain like vineyards significant delay routing troops who have no such interest?

I suppose this is one of those situations where having some light or medium foot troops to pursue would be handy.

The rules allow the routers to wheel to make the best distance to their base edge. However, if there is no obvious way around, I imagine people running in fear go in a straight line to try and get away.

If slowed down by a vineyard, it might be reasonable that the panic subsides a little and they can be more easily rallied. Maybe if it's too hard to run, standing and rallying becomes a better choice. A good excuse?