I recorded and uploaded this snippet of dialogue so anyone can listen and hear for themselves.
I also did an analysis of the audio using Praat: (click to enlarge)
There are two hyphotheses: (a) that the highlighted segment is the prefix pre- (b) that the highlighted segment is the word for. In fast speech, the /r/ part of both pre- and for will be very similar (and brief) so it would be difficult to tell them apart. So we have to see if the first sound is an /f/ or a /p/.
Knowing the phonetics of English, we would expect the prefix pre- to be pronounced as [pʰɹiː], with an aspirated /p/. Aspiration is realized as a puff of air which shows up on a spectrogram as a dark band. For example, if you look at the CH-sound of checking, you see a dark band where the /tʃ/ is aspirated as [tʃʰ]. An /f/ sound, as in for, would not be aspirated and so would not show up as a dark band on the spectrogram.
Now, if we look at the spectrogram for the mystery phoneme, we see no dark band, so we conclude that it is not an aspirated sound and therefore must be an /f/ as in for.
Also, as commenters and other answerers have noted, we have a major semantic problem if we assume she is saying "pre-delays"—it doesn't make any sense.