Did you check the replication lag on all clusters on the server your query was running on, or only one? The query killer (correctly) ignores the cluster the database cluster the query is running on, since queries on one database can still affect replication of another cluster.
The script was working with just one DB cluster (s3/s6), so I've checked just it's replication lag.
To be honest, I am not sure how s2/s5 or s1 replag could be connected to s3/s6 replag, my view was they are working on completely different machines. Could you please explain why think the script behaviour is correct.
mashiah