Sam Fisher- Paracord Lock

He found another short coil of paracord in his sack's side pocket and knelt before the door. He flipped the Tridents down and switched to night vision. In washed-out green and gray, the rusted door filled his vision. Above the latch was a U-shaped handle. Fisher gave it a tug and found it surprisingly solid. He rolled onto his butt, pressed the soles of his feet against the door, and shoved once, then again, and the door groaned shut.

  He looped one end of the paracord through the handle and secured it with a taut-line hitch, then threaded the other end through a rusted eye bolt in the jamb. He repeated the process, knotting and looping until he was out of line. He cinched the paracord with a bowline and stepped back to examine his handiwork. It wasn't perfect, he decided, but it would slow them down. The door hadn't sealed completely, but the gap was narrow enough that it would take some steady pressure on the door and persistent knife work to saw through the paracord.

- Conviction, Chapter 13