The rabbi said only two fallen angels survived the flood. I reminded the rabbi that some commentators say a third angel survived and her name is Bree Olson:
The story of the Nephilim is chronicled more fully in the Book of Enoch. The Greek, Aramaic, and main Ge’ez manuscripts of 1 Enoch and Jubilees obtained in the 19th century and held in the British Museum and Vatican Library, connect the origin of the Nephilim with the fallen angels, and in particular with the egrḗgoroi (watchers). Samyaza, an angel of high rank, is described as leading a rebel sect of angels in a descent to earth to have sexual intercourse with human females:
And it came to pass when the children of men had multiplied that in those days were born unto them beautiful and comely daughters. And the angels, the children of the heaven, saw and lusted after them, and said to one another: ‘Come, let us choose us wives from among the children of men and beget us children.’ And Semjaza, who was their leader, said unto them: ‘I fear ye will not indeed agree to do this deed, and I alone shall have to pay the penalty of a great sin.’ And they all answered him and said: ‘Let us all swear an oath, and all bind ourselves by mutual imprecations not to abandon this plan but to do this thing.’ Then sware they all together and bound themselves by mutual imprecations upon it. And they were in all two hundred; who descended in the days of Jared on the summit of Mount Hermon, and they called it Mount Hermon, because they had sworn and bound themselves by mutual imprecations upon it…
According to these texts, the fallen angels who begat the Nephilim were cast into Tartarus (Greek Enoch 20:2), a place of ‘total darkness’. However, Jubilees also states that God granted ten percent of the disembodied spirits of the Nephilim to remain after the flood, as demons, to try to lead the human race astray (through idolatry, the occult, etc.) until the final Judgment.