What is the ruling on delaying the Maghrib prayer until after its appointed time due to its concurrence with the time of a university lecture, in a situation where absence or lateness would result in the cancellation of the lecture?

The action is that you perform ablution and prepare for the Maghrib prayer before its time enters. When the time for Maghrib enters, you can pray in your study place during the three available minutes before the lecture begins. You are not required to go to the Musalla (prayer room), for the entire earth is a Masjid (place of prayer).