Thanks a lot, I don't know how I could forget that flag.

It is strange that sometimes 3 earthquakes destroy all walls, and next time it needs 9.

Within test, it looks like the upper tower is considered slot 28 if defender and all slots on. Checking his health with BM28:H?y1 gives 100. I configured the earth quakes to cast as long as y1>0 but does not work. The test messages gives me the health of slot 28 still 100, after it was destroyed.