I took it as Killua was trying to tell himself that it doesn't matter if the opponent knows what your technique is, especially when you can land a hit. That is what Hisoka warned Gon about Nen when Gon said "I could have used Gyo to avoid his Bungee Gum".
In terms of character personality, I like how Knuckle and Shoot seem to parallel Gon and Killua. Gon and Knuckle are more headstrong and in-your-face, while Killua and Shoot are more cautious. Only, Killua just got a truth train from Bisky, so now he is overthinking everything, both his habits, reactions, and his determination, which makes him fight even worse than he would have otherwise against a cautious opponent like Shoot. Like, it is a good thing to back off (or just take it like Hisoka) to figure out why you received unexplained damage in a fight.