I'm... unconvinced the drop rate is actually 10%. I've gotten 1-3 skulls each time. (7 times)

It is, however, quite low. With only 2 maps left, the drop rates are... concerning. Not really sure at this point what is best to farm. Presumably all but 1 of the items will have a better drop rate in the final 2 maps.

(and has anybody gotten the "2nd" girl from the last event from the gotcha? I haven't seen any indication she's there... (or the two girls from the event gotcha, either.)