If Army beats Loyola (and there is a 20% chance of that happening), Loyola would move:
RPI: 6th to 8th
Strength of Record: 5th to 8th
With a loss, they'd still have a top-5 RPI win and a top-10 RPI win.
Whatever you think of RPI, their resume would still be the 8th strongest resume in the nation. (And I think SOR is a better way to look at a team's holistic season than RPI).
Now, as far as getting a home game, that is much more in jeopardy should they lose tonight. In simulations where they lose to Army, they only get a home game in 79% of them. If they want to start their tournament at Ridley, they better win tonight.
But even with a loss, the Greyhounds are still an at-large team, whether you stick with RPI or want to look more holistically.