What is the ruling on a traveler performing the obligatory prayer in the mosque after the Adhan and before the Iqamah?

This act is not appropriate because it involves abandoning congregational prayer, and the Prophet, peace and blessings be upon him, forbade leaving the mosque after the call to prayer (adhan). What is appropriate is to wait to perform the congregational prayer, unless there is an excuse such as the fear of missing one's companions or being harmed by waiting. In that case, it is permissible for him to pray alone and depart, while explaining his excuse to the mosque's imam if possible.