Made a video showing me killing an Ice Burrower:
https://www.youtube.com/watch?v=5fsvt1xfuqY
This is only my second try, so I might be able to find a way to make the fight shorter. As it stands, my current strategy takes about an hour per kill, so it is definitely not a quick process for Shamans. The nice thing about this strategy is you don't really need Torpor. It would take even longer than in this video, since you couldn't heal with Torpor, but it would be 100% doable.