The Imam should make the Prayer short if something happens
حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ الْجَهْضَمِيُّ، حَدَّثَنَا عَبْدُ الأَعْلَى، حَدَّثَنَا سَعِيدٌ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِنِّي لأَدْخُلُ فِي الصَّلاَةِ وَأَنَا أُرِيدُ إِطَالَتَهَا فَأَسْمَعُ بُكَاءَ الصَّبِيِّ فَأَتَجَوَّزُ فِي صَلاَتِي مِمَّا أَعْلَمُ لِوَجْدِ أُمِّهِ بِبُكَائِهِ " .
It was narrated that Anas bin Malik said: “The Messenger of Allah (ﷺ) said: ‘I start prayer and I want to make it long, but then I hear an infant crying, so I make my prayer short, because I know the distress caused to the mother by his crying.’”