If the tunnels were death traps, Hamas casualties would be higher.
Regardless, if they had opened them to the general public, Israel would not have the same freedom attacking them.
Maybe a miscalculation on their parts, or maybe they see the civilian death toll as more beneficial for the 'cause'.
Israel did pressure Egypt to take in refugees, but was rebuffed. The point being that this part is Egypt's choice, not Israel's.
Obviously, this could have been done years ago, as well.
My issue is less with your post, and more with @thaibeachlovers constant nonsense.