I still have not found the second line and the tank of yellow ink is still covered on top with no other line to pick up anywhere, I have restarted the game 6 times and followed the directions diligently and still no second line
When you leave level 3 to the left, do you take the elevator down to level 1? You have to prevent that. Once you appear on level 2, you have to immediately walk right towards the yellow box. There you will find a line to pick up.