Answered by Shaykh Amjad Rasheed
How long can a person sit in the mosque before the time for praying the greeting of the mosque expires?
The length of time that causes the expiration of praying the prayer of greeting the mosque is being firmly seated. So if he sat quickly, such as someone who sits on his feet, the
n the time for the prayer has not expired. It is recommended for him to pray this prayer, as has come in the super-commentaries of the Tuhfa, narrated from Imam al-Ramli.
[Translated by Sr. Shazia Ahmad]