They need a lot of airway and exit tunnels - and not just for compression effects - a tunnel can become a very dangerous place very quickly: https://en.wikiped

They need a lot of airway and exit tunnels - and not just for compression effects - a tunnel can become a very dangerous place very quickly: https://en.wikipedia.org/wiki/Mont_Blanc_Tunnel#The_1999_fire https://en.wikipedia.org/wiki/Mont_Blanc_Tunnel#The_1999_fir...