Is it permissible for a traveler to shorten the 'Isha prayer if its time begins during his emergency travel, after he has prayed the Maghrib prayer in full?

If the time for Isha prayer began after you departed the town and passed its houses, then your shortening of the prayer is valid. However, if you shortened the prayer while still inside the town, what you did was incorrect, because shortening the prayer is not permissible until after one has left the houses of the town, according to the majority of Muslims. You must, therefore, repeat that prayer. Jurists have based this ruling on the Almighty’s saying: "And when you travel throughout the land, there is no blame upon you for shortening the prayer," and on the practice of the Prophet.

However, if you departed after the time for prayer had begun, by an amount equivalent to a prayer or one of its rak'ahs, then jurists have differed on the permissibility of shortening the prayer. Some have held that it is permissible if any time remains, even if only for one rak'ah, while others have maintained that it is obligatory to pray in full.