Another demonstration of the fragility of blockchain analysis.
While I realize you just meant it as a light "fun fact", I think it's worth pointing out that walletexplorer is very primitive and semi? unmaintained -- and you won't be able to trick any serious analysis tool with a coinjoin like that. [Although coinjoins can do an amazing job at tricking them! But you really need the coinjoin to look like a normal transaction for that]