On the level before secrets (the one were you first meet the enemy whitch runs on walls and shoots a red ball thing (the one whith the diner room with the small scorpian things and the worm thing ( you will know because in the tunnel there is eggs whith more scopians in them) were you meet them for the first time kill them then take the first door on the right you will see a tunnel whitch leads to another room where there is a second tunnel go through and take a right bingo there it is next to some intel

(sorry i forgot the name of the level)