Whether it's 50 or 70 meters, it's besides the point I think.
I really really hope l'm wrong, but the whole thing doesn't add up based even on the things we know for 100% that happened.
For example, take the reaction of Kate McCann when she raised the alarm as soon as she found out Madeline had disappeared: "they've taken her". Now imagine yourself finding out your child was gone? What would you do? Surely the first thing you'd instinctively do was look for your child (in the apartment and its immediate surroundings) and shout & scream his/her name? There is no evidence she did so. Instead, she head back to the tavern and screamed she had been taken. This leads me to believe that either Kate McCann was acting, or knew straight away that it was impossible that Madeline could have left the apartment/bedroom on her own accord, which is strange in itself.
And this is just one of a number of things which are strange.