Safe way- don't do it.

Use a proper rope, otherwise, you are playing Russian Roulette. 550 line (paracord) isn't very strong, it can loose half or more of it capacity due to knots. And gravity is always loaded.
_________________________
-IronRaven

When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.