They can't. Water is capable of cutting through steel when you slice it against the steel, at high speed, in a knife shape. Of you just create a drill of water and start rotating it, it won't really do anything. Also, it took both Katara and Aang (both master waterbenders) a really long time to cut through 1 pillar of steel, and eve after that they were exhausted.
Aang wasn't a master, and they had very little water to use. And again, this doesn't prove that drills cannot go through the earth.
Why do waterbenders need to cut through earth in the first place? This is waterbending, not earth. If anything, it seems unneeded to have a water move that'll cut through earth.
What if we are trapped underground by an earthbender? And besides, waterbenders need more moves that can have an affect above ground, too.
It doesn't need to, its waterbending for a reason..
Waterbenders are too limited, more so than any other element. Earth has all the land they could ever need, and freaking lava, air is literally all around us, and they have asphyxiation too, and fire doesn't require a source, and has combustion and lightning. Water is limited to the oceans, rivers, lakes, and ponds, which few people actually traverse, and our only sources of water on land are some limited plants and water bottles, hardly enough for much, certainly not enough for a combo, which also can't be used with plants. If a person wants to avoid fighting us, all they have to do is stay away from plants and water, which isn't exactly a challenge. Plus, bloodbending is usually disabled or reserved for paying players on most servers. Waterebenders should have more versatility. And besides, Ice drills are shown on the show, so I see no reason they shouldn't be included in the plugin. I don't think its too much to ask.
You can make a giant surge out of one plant, or make a surge shield out of a bottle, and 9/10 times it'll come back. Just because it's in the show doesn't mean it has to be in the plugin. Suffocate really isn't that good a lot, and you're immune to lava if you just stay in the water. Combustion is actually pretty pathetic, and lightning is predictable and inaccurate. You're also immune to lightning spreading if you're high enough on a waterspout. My point is, waterbending doesn't need so much power on land, and making a tunnel with water is more or less a luxury.
So what's your point? Waterbenders aren't alone - chi's and airbs can't get out of the cave as well, when it is occluded.
I just hate hearing "waterbenders are too limited";"they are limited to <...>, they must avoid being near a source". It is their aspect to be a waterbender. Saying that waterbenders must stay away from water and source, is like saying an earthbender to stay away from the ground.
No, she didn't.
Themselves, but not the air around them.