Olivia's Secret Room

trick also:
if everyone in the party types Olivia and presses Enter at the same time, more than one boss is spawned. in just 3 boss runs so far, i netted 13 dolls total (8 from the first, 1 from 2nd (partied with a friend who didnt know this tactic), and 3 from the 3rd (friend, friends friend, and me, each did the trick)).

I wish I had known this before...