Better ways to get out of invalid situations

For example, Pillar has a special case that allows it to swim up in water, but it can only happen if the start of your path is underwater (i.e. at the bottom of a river).

I think we should extend this idea to maybe also include lava (i.e. it's okay to traverse in lava if your starting point is also lava, it's okay to ascend out of lava) so that it can get out of sketchy scenarios instead of just failing instantly. Same applies to flowing water, you should be able to walk around within it, but not walk into it.

Needs lots of testing to make sure though.