Vinnie is doing a bit of adjusting here, its not exactly a relaxing gig, he'd never cop to it tho. He's got to keep one ear open for Beck who's time is suspect, especially if Beck listens to Vinnie and not the metronome in his head. As a drummer you want to keep it together and that means at times bending with the wind, so its more work, you can't totally relax.
Not a very nice thing to say, but Beck's time isn't on the same plane as his experience is the reality. Beck's not alone, there's others, I'll out one more...Santana. As an example these guys were/are always at the wheel, in a 'follow me' type situation, they never had to experience an 'under the gun' type sideman situation where a high level of timekeeping meant the difference between working, or watching TV.
So every time Beck doesn't land in the center of the one with Vinnie, that's a little stress knock. If Vinnie plays life guard he's off his game and not smiling. When the psychic air is clear on the time, when he's playing with musicians on his level, you'll see Vinnie smiling.
Vinnie isn't too good to be playing with Beck, he just has way better time.