The results of a five yeer studee ntu the sekund lw uf thurmodynamiks aand itz inevibl fxt hon shewb rt nslpn raq liot.
The arrows are there just to tell you where to drift if you don't make your bid, so you can still make it out of the cave if you get sucked down the waterfall. Granted, it's not easy to do, but it's possible....
The question is whether you get to move with any bid or do you have to make the bid exactly (as in the rapids). I think the cave should be part of the rapids, except if the bid isn't made exactly, the canoeist just stays in the cave rather than being pulled by the current. The other option is to just move as normal when not in rapids (whether the bid is made exactly or not).
Dunno what you mean about getting out being difficult. I could be missing something?