"Then why aren't you tryin' harder to take me in?"

There are no words for how suicidal saying something like this to Greg feels to Sans right now - he would sincerely rather die than risk going back to that place. He should definitely not be trying to provoke Greg into reconsidering. Yet... knowing the answer, or getting Greg to think about the answer, is the only thing Sans feels like he can do right now.

He stays down on the ground. He looks vulnerable. Come on, Greg, show him what's going on inside you head.

"That's... That's what Blanche wants. You know it is. He'd praise you for the opportunity to put me on a kebab again."