question #3 Sahih Muslim 540c, Book 5, Hadith 47 : What can be inferred about the direction of prayer when one is traveling?

We were in the company of the Messenger of Allah (ﷺ), and he sent me on an errand, and when I came back (I saw him) saying prayer on his ride and his face was not turned towards Qibla. I greeted him but he did not respond to me. As he completed the prayer, he said: Nothing prevented me from responding to your greeting but the fact that I was praying.