And since we can apparently pasken with stories, here’s a famous one:
A Jewish man who worked in Moscow’s diamond exchange was walking to work one morning, when an older fellow accosted him on the street and asked him to help make a minyan so he could say kaddish (he had a yartzeit). The man followed the older man into a small shul, thinking he was number 10, and the guy would learn some mishnayos, say kaddish, and share some nosh. But upon entering the shul, he saw he was number 6, and the older man went back out into the street to find more Jews. He waited for a while as the man slowly found some other men, and finally there was a minyan. To his shock, the man began davening shacharis from the beginning. He felt some annoyance, and told the man he needed to get to work, but the older man shushed him and said he had yartzeit and would say all of the kaddishes and davening. The man grumbled, realizing how late he’d be to work, but didn’t want to break the minyan by leaving. So he stayed, and the older man davened the whole shacharis, said some mishnayos, and shared some nosh. When the man went back out into the street, there was a great commotion. That day, the Bolsheviks had staged a coup and taken control of the government, and Jews were being rounded up and arrested at the diamond exchange. By delaying him with the davening and kaddishes, the old man had saved his life.