“But, my guess is, four women could do the deed in a moderately large restroom...”
Doubtful, even a first trimester abortion would require a certain amount of equipment. Any abortion (induced or spontaneous) requires that the fetus and placenta are completely gone from the uterus. This is not something you can check for in a public restroom. If it is not all removed there is a very serious risk of sepsis to the woman.
I believe that it was an abortion pill abortion.
They (wrongly) send these home with women.
Mail order even.