I say go anyway. Awkward situations are a part of life and at least this one is in a public setting.
I highly doubt that either of the two will be waiting there with a bouquet of flowers and a ring in front of everyone and making the other jealous.
Do they know that the other likes you? I say tough shit. You're allowed to go visit who you want and if they can't handle seeing you, that's their problem. They can make excuses to either be out of the office or too busy to talk to you if they wish.
Don't NOT go some where or do something because it might make others uncomfortable. Only if it'll make you uncomfortable to see them. ( I can only think this would be the case with the one you actually like). And who knows, maybe you guys will get back in touch and be good friends again!