At some point during his attempted coup, he realised it wasn’t going to work
When was that, exactly? Putin fled, reserve forces were standing by and not fighting Wagner, and he was a day out from an undefended Moscow. Worst case scenario was a protracted civil war, but he still would’ve lived longer than this.
Honestly, none of this makes sense. The fact that he aborted in the first place makes the idea that he was conspiring with Putin the whole time to flush out disloyal elements within the Russian armed forces seem credible… but then why kill him after? I’m not ruling out the possibility that either this was a genuine accident, or it was another false flag and he and his second in command just faked their own deaths.