Inside the Seventh Elder's pocket is the phone he uses to contact the Wanyan Family. This phone still contains the text messages he sent to them.
The Seventh Elder doesn't know if Ye Qing has already discovered his identity, but for safety's sake, he plans to destroy the phone first. If Ye Qing hasn't realized he's a member of the Wanyan Family and later discovers this through the phone, wouldn't that be asking for trouble?
Ye Qing is unaware of this; he's been worrying about whether the Seventh Elder has contacted the Iga-ryu side, so he hasn't noticed the Seventh Elder's subtle actions. Upon hearing the Seventh Elder's words, he smiles slightly and says, "I've changed my mind; I'll personally handle the matter of rescuing Zi Yu. During this time, I'm afraid the Seventh Elder will have to endure a bit."
