"But they still don't have knees, so they can't kneel." 
This conversation is just going on in the middle of a sidewalk, yes. Well, pavement leading to a sidewalk, to be precise. 

"Maybe there isn't a word for it," offers the wise one.

He starts to whine, "But I suck at naming."

"Would that be important? I can't do it anyways," he reasons.
Later? It's never going to get done, anyways.

Okay, they're never going to do it.
"I guess," he says, wriggling his head a bit.

"It always hurts," he says with another wriggle of his head. Ordinarily, one would call that a nod, but it's different enough to not be called one.

No, it's not.
"Yeah, it always hurts," he repeats.

Well, much better than punching his head, which he usually does to himself.
He looks at her curiously while she nears, but he doesn't seem threatened. Which is good, because when the Mamba feels even remotely threatened, he starts showing his lack of knife skills. That being said, though, his bright green eyes isn't what gives off that impression. They just give that off-edge, deranged feel as usual.

Well, the Apologetic Assassin hopes they're both proud of themselves, for spearing through a building and making its top half explode.
The Mamba is acting more like a doggo than a snake. He closes his eyes and leans into her touch.
At least his head doesn't sound empty and make echoing noises when she taps on it.

The A.A.? Avoiding the unnecessary, possibly expecting the two of them to figure out a course of action for themselves. Which they are obviously not doing, but hey.
Honestly, how do they even stay like this? The scene is pretty chaotic. There are a bunch of police cars and ambulances all over, and also there's been fire trucks. The narrator doesn't know how they just ignore everything, but then again, that's like these two's superpower.

"Okay, then stop," he says as his way of agreement. He also proceeds to forget to say thank you. Yep, this dude has like no manners.

Completely oblivious to how "get going" contradicts completely with the "stop" he just said, the Mamba wobbles upwards a bit, just to shrink down more after around four seconds.

Well, now he's not budging. The strange thing is that he just closed his eyes, as if meditating. As if. Meditating would probably help a lot.

Oh, now the narrator has been tempted. Thanks a lot, Cheetah.

Oh, but he doesn't fall over suddenly! It's more like he turned into an elongated, stiff piece of cardboard and is getting slowly blown over by the wind. 

Anyways, he falls onto his face.
"Whoa there," says someone. "You alright?"
There's someone standing a few yards away. Somehow, his voice carries.