I've made the scenarios in my head and the one more prominent is we play one hell of a game, like the one vs Madrid...then after leading 3-0 you hear...HALMA!...and then you know the rest.
Simeone gambled by substituting all three players at 66th minute and it paid off but I find it's rare. What if Oblak injured a few minutes later and opponents tried long range strikes and Atletico ended up losing big score.