"Rob started Snapchatting his thoughts and his feelings, and that's really not like him," Kim recalls in the clip.
Upon arriving with her mom's boyfriend Corey Gamble to check on him, he reveals that the police had already just done that.
"That's crazy, the police just came - like eight of them, or whatever," Rob says, apparently not realising the reason behind their visit. "Do I look drunk in the video or something? I don't even drink."
But Gamble breaks the news to him as artfully as he can: "People that don't know you are going to get the idea that you were suicidal," he explained.
Rob explains why he posted the sobbing Snapchats, telling them he wanted people to know he was hurt.
"The fact that she said: 'Okay, if he doesn't have his sh*t together in a year, I'm going to drop him'... like, who are you to say [that]? How much do you guys want to bet - I'll bet money that she does not come back to me."
But Kim admonishes him for being so insecure and playing into Chyna's hands.
"What happened where you're so insecure that you think she has the power?" she says. "You have the power."
Kim admits that while she's "always been super cool" with Chyna, seeing her motives in leaked texts was "hurtful."
In a separate piece to camera that is sure to make awkward viewing for the almost-sisters-in-law, Kim reveals she doesn't think they work as a couple.
"I've always felt like that them as a couple just isn't that healthy, and I think they know that too," she says. "Rob can be really irrational and he just has to learn to really take responsibility for himself and not blame it on Chyna. This just all has to stop.
"It's so clear what this relationship is," she adds. "They're just not meant to be with each other."
On Wednesday night Rob and Chyna were spotted having dinner at Tao in Los Angeles, sparking reports they may be getting back together.
