After some discussion about this, we've decided that this isn't against the rules and the previous outcome has been overruled. This didn't harm the Innocent team, and so it was not against the rules. Kato was clearly trolling and should be more careful / hold back a little from this.
I'd also like to point out that the slay doesn't make much sense, as, even if this had been against the rules, Kato should have been teleported out of the way rather than being slain.
The punishment will be removed.