Third Rail EVP Update

See here for essential background: https://hpanwo-voice.blogspot.com/2022/10/evp-on-third-rail.html.
After writing the above and below articles I decided to do an accompanying HPANWO TV video, see: http://hpanwo-tv.blogspot.com/2023/03/evp-on-hpanwo-tv.html. One of my regular viewers, called Gary, is a sound recording engineer, an Englishman living in Mexico; and he offered to carry out a full analysis. As I explain, the HPANWO TV one disappeared, but the original Third Rail one is still there, so he focused on that soundtrack. I sent him all the clips I had made of the segment and waited for him to get back to me. When he did, he told me he had discovered something remarkable, that there are two anomalies on the soundtrack instead of just one. The noise in question consists of two collections of sound. There is a series of unintelligible warbling consonants and vowels and then straight after a brief pause a "hmm" sound. It turns out the two were created very differently. Gary thinks the first sound is not significant; it is merely Trevor's words distorted and fed back through his Skype channel after a delay because my microphone was receiving. The "hmm" doesn't come from either of us. It is also higher pitched and different in tone, a feminine voice. It has a different readout on his frequency analyzer; its waveform makes it look like it's been processed in a totally separate manner. I'll post Gary's screengrabs below. As I said in the background article, there is no mundane explanation for this I can think of.
See here for more background: http://hpanwo-voice.blogspot.com/2023/03/hpanwo-tv-evp.html.