I watched it live and I archived it, dunno how well I can compress it to upload it on site, probably will have to cut some fluff. The stream started around 1:02 my time and lasted 1 hour, 28 minutes and 49 seconds. Rusty has a tendency to suicide bait, he did it many times before in Twitter, once it corelated with apparent news of him actually chopping his head off only for him to return a few days later. I don't know if he's doing it as an edgy schtick or does he have some sort of actual obsession over death like Tomasz Beksiński, the son of the famous painter. I can give some lore on that later if you want.
He just talked about his music, listened to some of his songs and a favorite classical song of his, ate some fruits, smoked a cigarette, then tried calling someone, typed something out on his phone and decided to "chop the watermelon" with the guillotine.

After which he took the camera, pressed it against his shirt and "chopped the watermelon" after which it was a dead silence with his phone constantly ringing.

It's very likely that this was all meticulously planned by him and Mumkey being in on the plan, and by the moment he took the camera he switched the livestream to a prerecorded clip because why would he push it against his shirt just to reposition it?
I'm betting on this being a very elaborate piece of performance art that did it's job because the suspension of disbelief was unreal. Plus, the stream clearly got ended, either by hand or by a dead battery, and didn't went on until it got completely nuked by YouTube staff. There are too many things that seem deliberate here.
And truth be told, if he did actually cut his head off, we'd most likely see a stream of blood shooting out of his severed neck arteries at this angle and way more liquid spilling sounds would be heard. I just hope he really isn't like Tomasz Beksiński and it's all performative art under the Rusty Cage persona.