Nah, what Lim meant by a snake with no warning colors is he's a manipulater. He is being nice and acting friendly and like he's a caring and empathetic person to trick people into telling him when they want to rebel. Remeber we've been told over and over the Hounds are extremely loyal. He's socially manipulating our male lead to get him to let his guard down and confess. Which he almost did, he felt it for that brief second, could this guy be an ally? But he remembered the warning and stopped himself.
That's the most dangerous type of predator, the one who makes you feel safe before it eats you.

sorry but im having a hard time trying to understand this latest chapter... is snake guy a good guy after all? who's side is he on actually??