The idea that the High Priest wore a robe with bells and pomegranates in the Holy of Holies, and had a rope tied around his ankle is a Myth.

That robe was not even worn when he went in the Holy of Holies. The myth that he went into the Holy of Holies with a rope tied around his ankle is not true.

2. And the LORD* said to Moses, “Speak to Aaron your brother, so at all times he does not come into the Holy Place within the veil before the cover, which is on the Ark, so he does not die: for I shall appear in the cloud upon the cover. 3. Thus will Aaron come into the Holy Place with a young bull for a sin offering and a ram for a burnt offering. 4. He will put on the holy linen tunic and he will have the linen breeches upon his flesh and will be girded with a linen belt and he will be attired with the linen turban. These are holy garments, therefore he will immerse his flesh in water and so put them on. Leviticus 16:2.

There was no use for a rope around his ankle because he would not be wearing the robe with the bells and pomegranates, and no one would know if he fell. If he had not prepared himself and went in with sin, he would have died when one of his feet touched the threshold of the Holy Place, the entrance of the Sanctuary. A priest or Levite without sin could grab his ankle and pull him out. There is no record of any priest dying because of sin on entering the Holy Place as all these commands were taken very seriously.

The making of the Robe is described in Exodus 39:

22. And he made the robe of the ephod of woven work, all of blue. 23. And there was a hole in the middle of the robe, as the hole of a coat of mail, with a band around about the hole, so it would not tear.

This garment was made like a poncho, only narrower. It was open on the sides and had no sleeves, so it was like a narrow prayer shawl. Notice the band around the hole for the head so the garment does not tear. God thinks of everything, does He not?