First of all, let me preface this by saying I think our only shot at the tourney is winning the BTT. This post is certainly not trying to hypothesize a plausible scenario of us getting an at large bid...
With that said there is a small chance we end up with an equivalent RPI as them (61) if we go 3-1, and they go 0-4 according to RPI Forecast. I'd be very curious to see what the committee does with NW at that point.
If we are at out does that mean they're out too?
In this case, we'd have similar RPI, better SOS, and beaten them twice. We'd also have a better record vs top 50 RPI teams.
Northwestern would most likely end up 4-9 vs top 50, and 6-4 vs 50-100. We'd be 5-8 vs top 50, and 4-5 vs 50-100. Both teams would be 100% vs sub-100 teams.
http://www.rpiforecast.com/teams/Northwestern.html
http://www.rpiforecast.com/teams/Illinois.html
So, the silver lining could be a sweep today sabotages their resume
Even in that scenario you mentioned, they have a road win at Wisconsin, our best win would probably be the road win against NU or home against UM. There's not a ton of meat on our resume even if we do go 3-1 the rest of the way. We missed all of the chances at signature wins.