Intersting, and sad, story.

Four people sexually assaulted by one guy with a knife.

Phone call for help "You need to help me."

"... traced to the apartment block but police officers could not find the exact unit..." How big was that apartment block? How many apartments?

As far as jumping to almost certain death, I would do it to avoid burning to death. But to avoid one person with a knife, I believe I would fight. Falling that distance will probably kill you, a knife might not. Or you at least might be able to get in a few good whacks on the badguy before he guts you...