Where is that quote from, exactly? But yes, that would work. Multi-tracker lets you fire two weapons. So yeah, it lets you fire a suit weapon and quad gun, if you want.
Fun fact: There's nothing really saying what kind of model can fire the gun. So can an MC fire the gun? Yes, apparently, nothing stping it, and it doesn't even seem that silly, in the case of a Wraithlord or Dreadnight. Now, with Tyranids, it seems a little sillier, but fair is fair, right?
But here's where it gets dumb: Can a Walker, like a dreadnought use the gun? Nothing says it can't. And I dunno, maybe he can jack into it, or something. But then how do you say a rhino can't fire it? You can't. RAW, a tank can fire the gun.
See what I mean? RAW is often so stupid that reasonable people didn't even consider all the possibilities. THat's why I'm saying RAI is often better than RAW.
'Course, in this case, you'd have to decide where to draw the line, because GW hasn't. I think we can agree tanks firing the gun is stupid. But is an MC doing so?
BTW, crisis on the gun is one of the least crazy things to do with it. Vindicare SNIPING people with it totally works, and is way worse, as is an Eldar exarch just ignoring cover with it, and shooting it twice for no reason.