Currently there is no built-in feature in cloud run where you can immediately/abruptly shutdown your old revisions whenever you deploy new revisions.

As documented, Cloud Run sends a SIGTERM signal before it terminates an instance, this is done so users can Gracefully terminate their applications. SIGTERM signals are sent in the event that there is a scale down or deleted revision.

When a revision does not receive any traffic, by default it is scaled into zero instances. The approach you can do is to manage your revision, make the latest revision to serve 100% of the traffic. However only new requests will be migrated to the new version as requests currently being processed will continue to completion, referring to this Stackoverflow link,

Cloud Run will continue to handle on-going requests on the existing instances of the old revision. The instances on the old revision will only shutdown once all requests are handled and be idle for about 15 minutes. Only the new requests will be routed to the new revision.

If you want to kill the Cloud Run old version immediately, you can raise the Feature request explaining your use case and requesting for the feature. You can follow this Guide for raising feature requests.