Talking about... divorce. In the context of unavoidable circumstances. For example, when a husband gives his wife a conditional divorce, to prevent her from being on limbo, or needing yibum. Also, some historical context. The sages stipulations regarding day of marriage was from the time of Ezra - because before then, the court met every day, and any woman could marry on any day. The sages or elders themselves delved into every detail pertaining to the wedding. Plus, an answer to why the virgin couldn't marry on Sunday. Also, what happened during a time of danger (oppression)? And how a Friday wedding for a virgin might risk breaking Shabbat. And how the Roman oppressors took the virginal brides (which seems to contradict the mishnah...so why is it the mishnah??).