According to the Gaza NGO Safety Office:
On 30 Sept., a Hamas operative died due to a tunnel collapse in Nuseirat Camp.What is the Nuseirat camp?
It is a crowded UNRWA camp right in the middle of Gaza:
It is not near any border with Egypt or Israel.
So any "tunnel" being built there is really an underground weapons depot, where Hamas hides rockets and explosives. And they are deliberately building these terror bunkers directly under the feet of tens of thousands of Gaza civilians, in a camp that was established by the UN.
Keep in mind that Hamas controls all of Gaza, including the areas that are not crowded at all (as you can see from the photo, there is still plenty of green surrounding the camp.) They choose quite deliberately to build their terror infrastructure in such a way that civilians are acting as human shields.
Not that Human Rights Watch will notice it.