One could imagine if Duan Ling Tian really became the direct disciple of the Sect Leader of Fire Worship Sect, he would have to bow his head and ask for forgiveness from Duan Ling Tian if he wanted to stay in the Fire Worship Sect. Naturally, he did not wish to leave the Fire Worship Sect! Moreover, he was even more unwilling to bow or kneel in front of Duan Ling Tian!
For this reason, if Duan Ling Tian really possessed an indigo Innate Spiritual Root, he would only be left with one option. He would have to kill Duan Ling Tian, this threat, in the cradle before the Sect Leader of Fire Worship Sect came out of his cultivation.
Naturally, if Duan Ling Tian only possessed a blue Innate Spiritual Root, the matter would not be so urgent since people with blue Innate Spiritual Roots would not catch the attention of their Sect Leader.