OTOH, this tunnel was a bit different. It went through a hill to supply front line trenches from the relative safety of the far side of the hill. It was much bigger than the mining and explosive tunnels dug into no-man's land. Eg the report says they found large amounts of equipment stored there, railway sleepers, machine guns, ammunition dumps, etc.

It would have had a lot more traffic and have been larger than other tunnels. Losing 2 companies of men in there is a not-insignificant war grave.