Daimotic sorcerers can already more-or-less "see" the Outside without becoming crazy (or sane?) enough to join the Consult and commit the kind of atrocities Shae describes.
It's one of two things in my opinion:
1. The IF is not actually a compulsion device per se, it just happens to have that effect if you want it to. When you look into the IF, you see (and perhaps more importantly, feel) the reality of your own Damnation, and just how ridiculously shitty that is/will be. So if, after experiencing that, the first thing you're accosted by are a group of powerful and dedicated folks whose entire goal is making Damnation not happen, you may be inclined to join up with their cause. It's like taking a dude out to the desert and waiting until he's dying of thirst, then offering him some water. He might still not like you, but he's probably gonna drink the water.
The issue with this is that it only works as a method of compulsion if there seems to be no better alternative. That's key, and I think it's the reason we haven't heard of someone who has seen the IF but didn't join the Consult (I suspect this will end up being Seswatha, but that's another theory, another post).
2. The other option is that it's simply a magical compulsion device meant to force anyone who looks at it to join the Consult. I think this is actually clunkier, since the IF being legitimate explains a lot about the Inchoroi (why are they so driven? how did they know about Damnation in the first place without actually dying?) while still being able to ACT as a compulsion device when used correctly. If the IF really is bullshit, then all that goes out the window.