We found out S"T morning, so the nighttime Hakofos were the regular beautiful long yeshiva hakafos (approx.. 35-40 min each)
Our local Hatzolah head called out the Rosh HaYeshiva after he finished shachris shmoneh esrei. Apparently, there was an emergency medical transport sheilah that had become more complicated due to the war. That is how the R"Y was informed of the situation.
After Chazaras hashatz, before hallel, we said tehilim 79, 83, & 142. We weren't sure what happened, but we knew it had to be very serious because in general, the R"Y is not pro public tehilim on Shabbos/Y"T. We also knew that it had to do with E"Y because of the choice of Kapitlach. But not much more than that.
During the kiddush, we found out a bit more information, but we were still very much in the dark.
When we came to Yeshiva for hakafos, instead of starting Ata Hariesah, we first had a 1/2 hour of tehillim. Then it was announced that the hakkofos would be shortened to about 15 min each (instead of 40) and there would be a seder limud afterwards. But we should still dance because it's the mitzvas hayom.
In the end, the hakafos took about 20 minutes each (there was a short shmuess from the R"Y/Mashgiach/ a R"M between the hakafos) and the mood was definitely more subdued. Some of the regular songs were switched for bitachon/yeshua songs and the Hoshia-Nas at the begining of each hakafa were much more heartfelt. There was a 45 minute seder and then the rest of the day followed as usual (aliyos, mussaf, mincha, seudah)