I say, with Allah's guidance: It is disliked to perform voluntary prayers in this situation, as it causes the obligatory prayer to be missed for something that is not obligatory. One leaves what is required and does what is not required, and this is not the action of rational people. Rather, if the following time is a time of corruption, such as the time of sunrise, one should leave the obligations and suffice with the minimum required for the prayer to be valid. See: Maraqi al-Falah and Hashiyat al-Tahawi, p.191. And Allah knows best.