Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) says: "The prayer begins with the takbir and ends with the salam. When you have said the salam and you are in a hurry for some need, then get up and leave without turning to face forward."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators are the narrators of the "Sahih".
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2604