The team does not walk blind.
Before the team moves, the recon drone is already gone. It flies point ahead of the patrol, scouting the tunnel and sending its feed back to Lucy at the command unit. Four rotors, a camera gimbal, a sensor package, and spotlights for the dark, on a rugged frame built for tight caverns.
The team does not walk blind because this drone walks first.
Technical schematic of the recon drone, side and top views.