Complex sentence: When faced with this situation, IDF commanders have either called off the bombing or launched a newly developed, relatively harmless, non-explosive missile at empty areas of the roof, in order to frighten the people gathered on the roof into leaving the building.
Split into simpler sentences: When faced with this situation, IDF commanders have either called off the bombing or launched a relatively harmless non-explosive missile at empty areas of the roof. This was meant to frighten the people gathered on the roof into leaving the building.