I really doubt you will have any problems. There is possibility that after a lot of usages, JVM will optimize your code so invoke will run a faster but never as fast as direct call. You might want to debug invoke method to see how many actions are done, you wont be able to monitor native method call though. In Java 8 with Functional Interfaces most likely you dont really need to use reflection, so giving us what you really want to do and we might give you better solution.
Next thing is that you need to make a lot of catches & in future while you or someone else changes name or parameters of doDie method, you will find out about this code when your server crashes.