>>537611491
>I figured that for imperfect cell its the matter that they're still in fucking around mode at first and then later its that he's just that much stronger that only 16 has a chance without getting absorbed in the melee
18 did think 17 and Piccolo weren't taking him seriously, but no matter how bad things got, she never tried to help.

>though i understand that's somewhat headcanon fueled by the History of Trunks.
In the Ova yes, they did fight together, but in Toriyama's version, 17 killed Gohan alone, so Toeir are the ones who really pushed 17 and 18 being team players. Might have been the case for Black and Zamasu as well.