Dalek Sec Hybrid Wasn't Exterminated

All the tie-in books, magazine articles and YouTube videos about the 2007 2-part storyline "Daleks in Manhattan/Evolution of the Daleks" claim that Dalek Sec Hybrid (the fusion of Dalek Sec and the human businessman Mr. Diagoras of 1930s NYC) was exterminated by Daleks Thay and Jast for his changes in ideology and his betrayal of their obsession with genetic purity. This, however, is not the case.

For those who don't know, Dalek Sec Hybrid underwent a significant change in behaviour and almost a redemption arc with some major character development, especially in the second half of the 2-part episode. To the point where he changed the Cult of Skaro's plans without the other three knowing, and required the Tenth Doctor to remain alive as part of his final experiment into human-Dalek hybridization.

What the tie-in media and YouTubers get wrong, however, is the fact that Dalek Sec SACRIFICED himself willingly to block Thay and Jast's attempt to kill The Doctor. His last words were literally "The Doctor must live!". Luckily, The Doctor interfered with their experiment beforehand anyway, and the lightning strike on the Dalekanium-enhanced Empire State Building caused his Time Lord DNA to corrupt the Human Dalek drones, giving them a degree of free will. This led to Thay and Jast being defeated by their own slaves' weapons.

Let me know your thoughts on Dalek Sec Hybrid's sacrifice in the comments below.