Go to the back cabin, there is a mechanism to open the tunnel. You have to hit 1 chainsaw (there are two) to get a key after going down. Get the key, come out from the enemy, open the iron gate, there will be a trap after entering the door, or hit four lights on your head. There will be parasites harassing you on the ground and money in the coffin. Then there is the most difficult part of this small pass-the mine car. After the mine car, take a disc (it seems that it is not round, it is a polygon). This is the so-called "sacrifice", and then you can go back to the front, press something for the lion and get on the elevator-pass the customs.