How to Inject JavaScript from Global Event Handler

What is the best way to inject a JavaScript reference to all the Kentico 11 admin UI pages from a Global Event Handler? I've tried accessing the ClientScriptManager from the sender object, but I'm seeing a lot of redundancy and potential null reference exceptions that I'd prefer to avoid. Could I perhaps inject an HTML script tag from my code-only custom module where the global event handler is defined? I'm open to any ideas on how to best accomplish this customization.