We have learned that you do not mess with William Devane! He may be old, grizzled, and paunchy, but he will still FUCK YOU UP! (Even if it takes at least one incredibly obvious stunt-man replacement shot to do it.)
I hadn't known he was going to be on, so I was thrilled to see him in the credits and then in the flesh. Always fun watching the old pros together and you could see how much fun Harmon was having, the same way you sense how much he likes working with Ralph Waite. (And of course, David McCallum.)
On the other hand, someone please, please, please tell me that those interns were a one-time thing to pad out the episodes and will never, ever be seen again.