I mean... Krazy-8 tried to kill them and Walt postponed it. And he likely would've tried to kill them if he got away (if he survived long enough).
But Walt killed him while he was bound at the neck by a bike lock. I wouldn't call trying to escape the murder room "actively trying to kill them". That was just Walt straight up murdering him.
Krazy-8 was less of a threat than Gale at that point, Gale could've still hit Jesse with a tea pot.
The way I see it, Skylar is "naive" because Walt is still lying about the violence. He always says that she shouldn't worry and they are safe and he often frames it like Skylar is being ridiculous for worrying. Gaslighting works, that's why Walt keeps doing it. I don't think she would be doing any of this if she saw Walt murdering Krazy-8.
You already saw the guy that came to use the bathroom in the first episode of this season, he was in Saul's office wearing a "Security" jacket, telling a customer that they are closed. Then he was standing next to Saul when he was outside calling Skylar and Saul asked him "You got a passport, right?".