It's tragic to see all of those people at in the windows. Unfortunately, there wasn't any way to get a rope or harness to them.

A helicopter's main rotor blades only let a chopper get so close to something like a building. In retrospect, it might've been possible to jury rig some form of pole that could hold a harness out beyond the rotor blades. When the victim grabs the harness, it would disconnect from the pole and the person would swing below the chopper. It'd be tricky, especially if no one had practiced this before, but it might possibly work. Unfortunately, that would only let you rescue one person per flight. That would've only allowed a tiny fraction of the people trapped in the towers to be saved, but it might've been better than nothing.