Salaah

Shortening one's salaah if one is afraid that someone might come in the room

Q: Is it sinful to shorten a prayer if you’re either afraid if you don’t, then someone might come in the room and mistakenly walk in front of you or because you don’t want them to hear you (I deal with anxiety)?

A few weeks ago, I shortened a prayer once by leaving some sunnahs due to the first scenario. Do I have to repeat it?

Imaam informing the congregation that the salaah has to be repeated

Q: One day I was leading three people in zuhr prayer. In my second last rakaat I felt like something was coming out from my private part. I still continued with the prayer. After I finished I went to the toilet and I found it was mazi. I came back after I washed myself and made wudhu but the people we prayed together with were gone. I don't know where to find them because it was a market where we prayed. I don't know them at all. I then observed the prayer alone again. So what should I do about them?