In His House He Waits Dreaming

Expanding on a solo strategy in the comments of In His House He Waits Dreaming (25 player):

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2. Stand on Sara and kill the adds, they will explode and damage her triggering Phase 2.
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4. Kill the tentacle that grabs you at the beginning of Phase 2 and wait for the portals.
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6. When the portals spawn, stand near them, but DO NOT go into them yet. After a few seconds, voices will start talking and tell you which vision is inside the portal.
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   • If the voice begins with "it is done" = The Forging of the Demon Soul
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   • If the voice begins with "bad news sire" = The Assassination of King Llane
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   • If there is no voice = The Tortured Champion
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8. Enter a portal if you need the vision, you will instantly get credit for it.
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10. Otherwise, wait for another set of portals to spawn. Each new set of portals is a random vision, so just wait for one you need.
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12. After you enter a portal and get credit for that vision, wipe by letting your stacks of Sanity drop to 0.
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14. Teleport back to Yogg and start the encounter again to get your next vision.
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You should be able to get this achievement in one run with 2 wipes.

During phase 2, you need to witness all 3 different visions of Yogg-Saron. This achievement can be obtained in multiple runs, so it's not obligatory to go for all 3 within one run.

I was going crazy not understanding the "voice begins" and was checking chat, it is purely audio and had to turn my dialog sound to max and then poof easy!