The tunnel that they continue in slopes slightly down, but mostly it goes straight now, further and further. At this points, all the offshoots of the tunnel are much smaller, not all dormouse sized but none bigger than a rabbithole.

As they walk, the breeze that goes past them becomes more noticeable. It seems to be going outwards for a few minutes and then change direction to blow the other way, into the direction of whatever they're headed towards.... only to a few minutes later to head outwards once more.