فَٱلْيَوْمَ : Prefixed Particle "Fa" conjuncts clauses, semantically signifies cause and effect relationship and shows that later is immediately subsequent to the former in time. It is الفاء الفصيحة; for eloquence. It conjuncts to an elided element whereby it adds fluency and reveals the elided element. Responding to his announcement of belief and becoming a Muslim he was rebuked:

His hope and possibility of rescue has already been declined. Suffixed time adverb relates to the following verb and denotes the Day of Exodus. Thereby, the elided element of conjunction particle (الفاء الفصيحة) is self evident to Pharaoh and the readers of the Episode. After rebuke of his submission he was reminded he was given enough time and opportunities to mend his course of conduct. Since he failed thereby that day was the end of his respite period.

 نُنَجِّيكَ: This verbal sentence comprises of Verb: Imperfect; First Person/Sovereign singular; Masculine; Mood: Indicative; [Form-II]; Subject pronoun hidden; Suffixed Object: Second person; masculine; singular, in accusative state; مصدر-تَنْجِيَةٌ Verbal noun.  The irreducible features embedded in the Root and form of the verb are rescuing a person from a dangerous and unpleasant situation to a safer place and render him a saved person. Form-II adds attributive-Estimative/Declarative connotation: it makes an attribution to object; to consider someone or something to be something.

In straight and literal sense it therefore unambiguously means: "Our Majesty will rescue you, O Pharaoh". But in the context, it is evident that these are not the intended meanings, notwithstanding the sentence means so. This is what in the figures of speech is called Irony. This figure of speech is mostly used in the Grand Qur´ān in the context of afterlife, the day of resurrection and the upshot of criminals.

Therefore, we will have to estimate sardonic meaning running contrary to the first apparent meanings. Pharaoh was about to die. Thereby, the sardonic meaning of:  نُنَجِّيكَ will be "Our Majesty will render you rescued and relieved." Truly, irony is an insult conveyed in the form of a compliment.

It is obvious that here it does not signify rescuing him from drowning. Ever since Mūsā [alai'his'slaam] had come to him as Messenger he was constantly in stress and fear of his overthrow and losing kingdom. He openly alleged it as desire of Mūsā [alai'his'slaam] and his brother. What a superb sarcasm!

The circumstantial clause relating to his preservation was: بِبَدَنِكَ : بـِ Inseparable preposition is used for accompaniment, in Arabic لِلمُصَاحَبَةِ,  and its object noun: بَدَنِ is the head noun of possessive phrase, and "كَ" is second person masculine pronoun, referring addressee Pharaoh. Verbal sentence and this circumstantial clause would literally mean; "Our Majesty will render you rescued and relieved of fear in the sate your بَدَنِ is accompanying you."

Noun: بَدَنِ is from Root: ب د ن. Classical Lexicons give us its meanings as:

(مقاييس اللغة)

الباء والدال والنون أصلٌ واحد، وهو شخص الشيء دون شَوَاه، وشَواهُ أطرافُه. يقال هذا بَدَنُ الإنسان، والجمع الأبدان

لسان العرب

والبدنُ من الجسدِ: ما سِوَى الرأْس والشَّوَى،

الَبدَنُ الدرعُ القصيرة

That it is the apparent form - body of a thing other than head and limbs: torso: the human body excluding the head and limbs; trunk. His definition in relation to animals matches carcass: body of slaughtered animal for meat, with the head, limbs, and entrails removed.

This signifies small armour: coat of mail worn on torso.

It is thus evident that it refers only a part of human body, that is torso and not human body as a whole for which is the Root: ج س د . Torso is only a sub-category of human body.

It is evident from the imagery of scene that it does not refer to torso of Pharaoh but to his precious scale armour on his torso, which was distinction and recognizing symbol when crowded by people. The pharaohs often wore scale armour with inlaid precious stones. Often the use of scale armour was symbolical or for ostentation.

All English translators have rendered this verbal sentence as was done by pioneer translators:

George Sale: This day will We raise thy body from the bottom of the sea.

John Rodwell: But this day will we rescue thee with thy body.

Words "with thy body" are redundant with "rescue" since it is already in it.

Classical exegeses did mention its one meaning as: درعك "your corselet"

تفسير ابن كثير: وقال أبو صخر بدرعك

تفسير الجلالين: فاليوم ننجيك) نخرجك من البحر (ببدنك) جسدك الذي لا روح فيه

فتح القدير:وقد اختلف المفسرون في معنى ببدنك، فقيل معناه: بجسدك بعد سلب الروح منه، وقيل معناه: بدرعك، والدرع يسمى بدنا

They however erred when they opined that: ببدنك means:  جسدك الذي لا روح فيه your body without soul: dead body. It was error since: جسد refers the whole body of a man whether alive or dead, while بدن signifies only torso of human body.

Thus it is self evident that: بِبَدَنِكَ has only one meanings "with your scale armour".