Is a person allowed to swallow water in his mouth at the time of the Fajr اذان (call to prayer) unintentionally?

The Prophet's (peace be upon him) hadith: «If the call to prayer reaches one of you while a vessel is in his hand, he should not put it down until he has satisfied his need from it,» is evidence that it is permissible for one who is overtaken by dawn while holding a vessel of food or drink to complete his need from it. This scenario is an exception to the verse: {And eat and drink until the white thread of dawn becomes distinct to you from the black thread}. Some scholars deem this act permissible.