Reference: al-Fataawa as-Sa’diyyah – Page 128, Question 20
Question: Is it permissible to stand infront of the imaam [during the prayer] if there is no room left in the masjid?
Response: The prayer is not correct infront of the imaam, whether the masjid is cramped or not; However, Shaykh Taqee.uddeen al-Hilaalee is of the opinion the prayer is correct where the situation necessitates.