B flash out of tunnels

Stand still and jump-throw: hold left click, then jump and let go at the same moment.

From upper tunnels. Stand against the right wall of upper tunnels, by the pillar. Aim at the wall just under the wooden roof beams.

Practice (with sv_cheats 1): setpos -1624.03 933.31 35.10;setang -19.43 126.20 0