You can consider this as Derek's memory or as an illusion sent by the demon. At the very least, look at it as a prologue. In any case, since Derek is in the eternal loop of degradation, there is no strict concept of time here.
Here will be some sloppy seconds of Derek's (once a college graduate) eternal damnation, he doomed himself long time ago, or maybe tomorrow. There are not real timeline, just enjoy if you into this.