UPDATE: IANAL therefore this is opinion only. (Thanks for that catch there u/JollyRancherHard )

By not approving the mistrial, the Judge opens himself up to lega consequences beyond the normal when this is overturned on appeal (if it gets that far).

In this case it could open him up to criminal charges, disbarrment, sanctions, etc.

As it questions his judgement, additional side effects could be as bad as to call into question previous rulings, rippling through his legacy as a judge. Not a bad thing in this instance.

By not approving the mistrial, the Judge opens himself up to lega consequences beyond the normal when this is overturned on appeal (if it gets that far).

In this case it could open him up to criminal charges, disbarrment, sanctions, etc.

As it questions his judgement, additional side effects could be as bad as to call into question previous rulings, rippling through his legacy as a judge. Not a bad thing in this instance.