The river is all one sheet of water and the opposite bank is far off. When Suhni got into the whirlpool, her heart very naturally as it should be, trembled (due to her precarious position). It was only because she relied on the 'solace of the two worlds' (i.e. the Prophet) that she was able to keep her wits intact. The surf would be ineffective against her, provided you (O Allah!) extend mercy to her.
Your Lord is enough as the Guide and Protector. (31, Al-Furqan).
Hazrat Ali's prayer: "My sins taint my innocence and bring down your wrath on me. For the sake of him whose obedience and love you have linked with yours, protect and pardon me this day.

The river is too wide, the other bank far off,
The possessed woman entered the dangerous waves,
Pressed for life in high water,
She recalled her past sins with trembling heart,
If you showed mercy, no one will be overcome by waves.

The river is too wide, the other bank far off,
Pressed for life in high water,
She recalled her past sins with trembling heart,
She found solace by remembering mercy of the Lord of both worlds,
If you showed mercy, no one will be overcome by waves.