Nehahra plays demos between levels, how?

[Baker]

Nehahra plays demos in between every level, or rather specifically at the beginning of the level as I recall.

How is or was this done?

I am probably more interested in the idea of a transitional level screen being displayed than playing a demo between levels but I imagine the solution is about the same as playing a demo.

[And I imagine the same method could enable playing a movie between levels like how FTEQW supports a couple of video formats like Q3 ROQ).