"The double front doors were skillfully camouflaged, barred up with meter-long sheets of old partially rusted tin with inch-thick boards nailed across them. Thick curved nails (glued with epoxy resin) stuck out of wood and iron. Everything was well thought out and the scenery looked convincing. To the right of the door frame, an inhospitable wire with two bare contacts was hanging. You needed to close them to make the bell ring in the depths of the apartment. In case everyone left the workshop, there was a way to securely close the entrance. For this purpose, a strong and heavy inter-door hook and a system of levers were used. The door could be opened and closed by means of two external rope ends tied to the latch. Seeing this mechanism in action always made an indelible impression on newcomers."