There are precedents. Normally, once the speaking time has been used up, whether for asking questions or debating a motion, the current practice is to move on to the next speaker. There have indeed been exceptions over the years, but generally speaking, in a case like this one, the next person on the list gets to speak.
If we had a lot of time left, I'd be happy to allow you the rest of your speaking time. However, there isn't much time and I'd like everyone to be able to have their allotted six minutes. We will therefore return to you in the next round of questions.