"I'm not lying," pouted Conan, folding his arms. Little kid logic, little kid logic... ah. "I really am a detective, and I'm really, really not lying!" He scowled at Hibari, radiating bristly childish offence.

He was playing off of memories of the detective boys here; how they'd act around things and what they did in situations like this. Spade had shown him well enough that his acting skills weren't up to par, and now, under this dangerous condition was definitely the best place to need them working.