What I believe happens is that when you don't trust the guy(s) behind you to do their jobs well, you try to do their jobs for them, which takes away from your ability to do your job.
If you have reasonable faith in your goalie, it's bad if someone gets by you. If you don't have that faith, it's REALLY bad, so you try extra hard to not make that happen. And like a day at the range, the ideal state is "relaxed enough to be loose without being so relaxed you have no precision." If you get sloppy at the range, you miss a lot. If you get tense, you miss a lot. You want that ideal middle state where you make it look easy. Same on the ice, I suspect.
That's my understanding anyway.
Which is not to say that the rest of the team wasn't stinky last night, because they were. I just personally think that one of the reasons was the "oh boy, Hu's in the cage" factor. Remember the Jekyll & Hyde days of Bernier and Greiss?