halacha theory - What happened in R' Chananya's penthouse (18 Dvarim)?

Speaking of Beyt Shamai, Yerushalmi Shabbat 9a also here:

Background:

"ואלו הן ההלכות שאמרו בעליית חנניה בן חזקיה בן גרון
שעלו לבקרו ונמנו ורבו ב"ש על ב"ה
ושמנה עשר דברים גזרו בו ביום:"

These are the halachos that were taught in the attic of Chaninah ben Chizkiya ben Garon: When they went up to visit him and voted, Beis Shamay held the majority over Beis Hillel. Eighteen decrees were enacted on that very day.

Action:

"אותו היום היה קשה לישראל כיום שנעשה בו העגל.
רבי אליעזר אומר בו ביום גדשו את הסאה.

רבי יהושע אומר בו ביום מחקו אותה.
...
תנא ר' יהושע אונייא תלמידי ב"ש עמדו להן מלמטה והיו הורגין בתלמידי ב"ה.
תני ששה מהן עלו והשאר עמדו עליהן בחרבות וברמחים.
תני שמונה עשרה דבר גזרו ובשמונה עשרה רבו."

That day was as difficult for Israel as the day the Golden Calf was made. Rebi Eliezer says, on that day they overfilled the measure. Rebi Yehoshua says, on that day they emptied it.

It was taught: R. Yehoshua taught, "The students of Beis Shamai stood bellow and were killing the students of Beis Hillel." It was taught: Six of them went up and the rest stood over them with swords and spears. It was taught: Eighteen decrees were enacted on that day....

Please explain what was going on in that penthouse and how those 18 regulations were ruled. Is that the accepted way of resolving Halochos, forcing the other side into the minority?