Rabban Gamliel says that three women may knead [dough for matzah] together, then bake it in one oven, one after another. But the sages say that three women may work together on dough, one kneading while another forms loaves and one bakes them. Rabbi Akiva says, not all women, nor all woods, nor all ovens are equally [efficient]. This is a general practice: if the dough starts to rise, douse it in cold water [to slow it down].
The Torah warns “you should guard the matzot” (Exod. 12:17), which leads to unusual precautions at every stage of the preparation of matzah. Our Mishnah gives a window into the daily lives of women working collectively in preparing for this festival. Rabban Gamliel seems most lenient, allowing them to work together through the entire process, whereas the sages prescribe a more efficient assembly-line production, lest the dough turn to chametz while waiting to be baked. Rabbi Akiva reminds us that even efficient models like that of the sages may be slowed by differential efficiency among the workers and their equipment. The “cooling” method described here indicates experience with such inefficiencies and the attempt to salvage the dough from becoming worthless as chametz. Later halakhah (See Shulhan Arukh O.H. 459:2 in comments of Mishnah Brurah) establishes a fixed limit of eighteen minutes from when the flour is first moistened until when it must be put in the oven.