Currently, there is no way to stop the ActionsRunner process in a graceful way (as this was found to clear the session and its references to those environment variables). It was designed in a way that allows an earlier created process to be reused in the future (defaults to end the process when there is no activity in 15 minutes) with other Nolio Actions that might need to run as that user - to offer better performance.
If this kind of feature is something you would like then please submit an Idea (or vote for any existing) on the Community. You can find the area to submit an Idea, here: https://community.broadcom.com/enterprisesoftware/home
From this URL you should be able to find the Idea area by scrolling down a page or two. There is an Add Idea button that you can click to describe the feature, product, etc..