Oh my gosh, I forgot to update this. I did it last week, easy as pie. You just go down to immigration and tell them you're in transit. They take your passport and come back within a few minutes with the boarding pass and walk you to security and then the lounge. The lounge is AWFUL, FYI. It helps to have a print out of your itinerary to give the immigration person. It is super easy. Interesting about Iberia MAD-ALG, it was operating last week, but perhaps it was ending for the season?