Q. K’vod Harav, I was in a shul with exactly ten people and four already davened. I was of those that had not davened. However, I am makpid to daven with asara mispallelim, as numerous poskim hold it is not tefilla b’tzibbur unless there are asara mispallelim.  (Igros Moshe 1:28-29) (although some say that with six it is tefilla b’tzibbur, I am of those that are makpid and I am reluctant to make an exception even for one time).
What should I do? Am I obligated to daven there? 
It would be very uncomfortable for me to tell those people that I cannot daven with them, as the Rav is meikel (even l’chatchila) and the other people there are chavushe people with long beards and they are being meikel (for whatever reason), whereas I am a bochur. What is the best thing for me to do? 
They could go to a different shul, but for whatever reason they were going to rely on six and not go elsewhere.
A. Horav Shlomo Miller’s Shlit’a opinion is that the correct course of action is to stay and maintain the minyan and not abandon them to be davening beyechidus, without one. The above is recommended unless you can get a tenth person to replace you.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a