question #3 Sahih al-Bukhari 990, Book 14, Hadith 1 : What should one do if they are concerned about the approaching dawn during night prayers?

Once a person asked Allah’s Messenger (ﷺ) (ﷺ) about the night prayer. Allah’s
Apostle (ﷺ) replied, “The night prayer is offered as two Rak`at followed by
two Rak`at and so on and if anyone is afraid of the approaching dawn
(Fajr prayer) he should pray one Rak`ah and this will be a Witr for all
the Rak`at which he has prayed before.”