I never planned on doing that because I thought it was too predictable and didn't add to the humor too much. My original plan was to have him say something crazier like "gimme some tacos!" or "rubber jump pants!" But the timing for him ended up being too short because of everything going on in the scene. It got drowned out a bit by everything else going on, but there wasn't any good way to make it more audible without making it sound like he was standing right next to Freeman.
At least you did intend to follow through with the crossover ( however short it was), though without the annotation I couldn't make out what was said. I guess we could count this as a Shepard's mind reference, though it would be neat if Freeman thought about it at some point. Other than that, it was a great episode. The next one will certainly NOT feature Massachusetts.