Ah how marvellous idea, that hole-in-a-wall tactic!
Might be fun! I hate it when the enemy attacks me and soon turns tail because it suffered heavy losses from my archers on the walls. Then i find them in the next battle again!
How can i punch a couple holes in my own wall? Maybe exit the town, let it riot and then attack with onagers? Might be useful to reduce (exterminate) part of the populace while i am at it? Ah, onward to let Alexandria riot!
I hope the Pharaoh won't stab me in the back while i am 'dealing' with my future rebellious city!

Y.