Yep, it is generally using meta knowledge to do the solo parkour down and bring the whole party through...
Except I'd done this trick several times before and what with all these revivify scrolls + Withers, I play my Tav daringly. Also, potions of Invisibility are always stocked up.
It sounds like rigmarole, but it's pretty time efficient. Last playthrough I used wyvern poison to knock Ethel down in one round, had to ease off to position Wyll closest.
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In initial playthrough, and full release play, no such hijinks. Aggressive exploring is fun, but with a hag who can do worse than merely kill, it's unwise. Probably will use a mix of summons and being methodical. I'll just use knocking out on her minions.