Ok so the currents in Mithalas city have just fallen. They're doable without beast. First let me preface this by saying this trick isn't really that important or quick. It get effectively gets you Spirit before Beast and it takes some time. But more importantly, its just a really neat trick.
Requires: Nature, Energy
1. Swim up and attatch to the large Jellyfish that's up-right of the entrance hallway (coming from Open Waters) using energy shots,
2. Navigate yourself on your Jellymobile down and around into the far right-hand corridor
3. Push him up until two Mithalan houses make an impass that the Jelly can't fit through
4. This is hard to explain (I'll make a vid shortly) but using briars, slowly wedge the jelly through the gap. You should be placing them at angles along the houses on either side. This takes advantage of the fact you can shoot briars through other briars and through the Jelly. Plant one on each house to wedge it in then keep alternating sides and planting one a little above the last. You'll eventually get it through.*
5. Ride the jelly up to the current
6. Attatch to rear of jelly and span energy shots into it and you will ride it through the current to the Mithalas Pot and Spirit Form!!!
* No Jellys were killed in the figuring out of this sequence break, though this process is probably close to being as morally reprehensible as monkey-launching.
Video:
http://www.youtube.com/watch?v=Xy1fwMDbrOo (may take a couple of minutes for youtube to process it)