The Imam is appointed to be followed

وَصَلَّى النَّبِيُّ ﷺ فِي مَرَضِهِ الَّذِي تُوُفِّيَ فِيهِ بِالنَّاسِ وَهُوَ جَالِسٌ وَقَالَ ابْنُ مَسْعُودٍ: إِذَا رَفَعَ قَبْلَ الإِمَامِ يَعُودُ، فَيَمْكُثُ بِقَدْرِ مَا رَفَعَ، ثُمَّ يَتْبَعُ الإِمَامَ. وَقَالَ الحَسَنُ فِيمَنْ يَرْكَعُ مَعَ الإِمَامِ رَكْعَتَيْنِ وَلاَ يَقْدِرُ عَلَى السُّجُودِ: يَسْجُدُ لِلرَّكْعَةِ الآخِرَةِ سَجْدَتَيْنِ، ثُمَّ يَقْضِي الرَّكْعَةَ الأُولَى بِسُجُودِهَا. وَفِيمَنْ نَسِيَ سَجْدَةً حَتَّى قَامَ: يَسْجُدُ.The Prophet ﷺ in his fatal illness led the people in Salat (prayer) while he was sitting (and the people were standing). Ibn Mas'ud said, "If anyone raises his head (while in prostration) before the Imam, he must prostrate again and must remain in prostration for a period equal to that he has lost by lifting his head before the Imam, and then he should follow the Imam." And Al-Hasan said, "A person who is offering a two Rak'a Salat with the Imam but (because of the rush of people) is unable to prostrate, then he should prostrate twice for the last Rak'a and make up for his Rak'a with its prostrations. And if somebody forgets to prostrate and stands up then he should prostrate." ​​