Is there any physical description of the Prophet while the Qur’an was being revealed to him? I mean his body posture, eyes open or closed, etc. Were there multiple witnesses with him when he was in the “trances”?
All I have found so far is:
" وَلَقَدْ رَأَيْتُهُ يَنْزِلُ عَلَيْهِ فِي الْيَوْمِ الشَّدِيدِ الْبَرْدِ فَيُفْصِمُ عَنْهُ وَإِنَّ جَبِينَهُ لَيَتَفَصَّدُ عَرَقًا"
"I saw it coming down on him on an intensely cold day, and when it had left him his forehead was dripping with sweat."
“One day the Messenger of Allah (ﷺ) was sitting amongst us that he dozed off. He then raised his head smilingly. We said: What makes you smile. Messenger of Allah? He said: A Sura has just been revealed to me, and then recited: In the name of Allah, the Compassionate, the Merciful. Verily We have given thee Kauthar (fount of abundance).” ... (sahih Muslim)
As-Suyuti in his itqan explained that what seemed to be a nap or a doz off for the sahaba or more exactly for Anas (who apparently saw this the first time), was apparently the kind of absence or state of absence that our Prophet experienced after a revelation based on ahadith like in sahih Muslim and sahih al-Bukhari (where this state was called الْبُرَحَاءِ).