I just tested and he continues, Black Widow's main scheme (50067b) is just taking her phase and not multiplying with the number of players. For example when playing in an expert match in the first part of the villain phase only increases 2 threat and should be 4 with 2 players or 6 with 3.
Her phase 3 (50066) is putting 13 HP per player, should be 20
I apologize if it sounds rude, English is not my primary language