According to Rebecca's autopsy report, a t-shirt was wrapped around her neck three times and I think double-knotted, and a sleeve was stuck in her mouth.
Her murderers wanted to make sure Rebecca would get strangled and suffocated by both the t-shirt and the noose, as well as make it impossible for Rebecca to breathe. Without oxygen or respiration, Rebecca was suffocated -- to simulate what her murderers thought Max had gone through, as alleged in Max's medical reports by Dr. Peterson.
No way no how Rebecca could have made it across the bedroom with her wrists and ankles bound and the t-shirt wound 3x tight around her neck and throat, a sleeve stuffed in her mouth, and a hanging noose around her neck, to leap off a three feet high balcony without making significant dust patterns with her feet and body on the balcony. A physical impossibility.