Well...what did they expect ? Hamas killers don't have to die, they can come out and surrender as the water rises..
https://www.frontpagemag.com/israels-enemies-up-in-arms-about-flooding-of-hamas-tunnels/ Another small detail I would add... I was stationed in Germany, near the Siegfried line..Germany's "last defensive line, before complete collapse.
I arrived there, 18 years after the war was over. I saw some oif the bunkers with walls and roofs 5' or 6' thick, still intact and some rthat were blown
apart.
Talking with the locals, I was told that vthe French were determined to blow up every bunker. The German Seigfried line and the French Maginot
line faced each other, just a few miles apart.
The French were not having too much success, blowing the bunkers/pillboxes up..even when they planted their TNT charges in the heart of the
structures.
It seems a GI happened along who was formerly an oil field worker, and seeing their problem, advised them to plant their charge in the bottom..then fill the bunker with water, before touching it off.
They tried it...and it worked ! Unlike air, water does not compress... So I suggest the Israelis where possible, plant their charges in the tunnels
BEFORE they fill them with water..