Romancing the Stone and it's Goof up...

You hear of goof ups in film, but I have never noticed one on my own...until last night. I was watching Romancing the Stone with my mum when we both noticed the goof. So Michale Douglas and what's her face are running from the crooked police. Then they come up to a cliff side. The only way across is a dilapidated old foot bridge. Michael Douglas decides to try and shoot them all, but what's her face has other ideas. She tries to cross the bridge, but the bridge gives out. She hangs onto one of the ropes and swings to the other side landing in the soft grass. Michael Douglas cannot keep the police away so decides to grab a rope and swing across. Instead of the nice soft landing what's her face pulled off, he crashes into the cliff side. This is when I noticed the goof. When he hits the cliff side it gives way like a sponge! You can see very clearly that the cliff side is made of foam/sponge.