Question: You often *plunge* into the sea or *plunge* you hands into your pockets.

Can the word be used to describe a "horizontal immersion"?

Example sentence:

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> She opened the door and **plunged** into the blinding sun.
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If not, what's a more appropriate word?

Answer: 
The OED's first meaning of ***plunge*** involves transitively thrusting, throwing or dropping something (or oneself) into a liquid - from the French ***plonger*** - *to jump into water, to submerge, or sink*

However, sense 4 (intransitive) of the verb covers precisely the circumstance you relate:

> 
> 4. intr. To move or travel forth, on, etc., rapidly, abruptly, or recklessly; to move with a rush or sudden impulse into or out of; to
>  hurtle, career. Also fig. 1726 W. Broome in Pope et al. tr. Homer
>  Odyssey V. xxiii. 256 He views the strand, And plunging forth with
>  transport grasps the land.
> 
> 
> 1806 T. Jefferson Let. 5 July in Writings (1984) 1165 If the
>  executive is to keep all other information to himself, and the House
>  to plunge on in the dark, it becomes a government of chance and not of
>  design.
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> 
> 1834 L. Ritchie Wanderings by Seine 110 We..plunged into the high
>  road leading to Duclair.
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> 
> 1885 Manch. Examiner 22 Jan. 5/2 Under a well-organised fire from
>  the works, the Arabs plunged forth upon the square.
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> 
> 1891 C. Graves Field of Tares iv. vi. 241 The Norwich Express,
>  plunging out of Liverpool Street Station.
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> 
> a1902 F. Norris Pit (1903) x. 400 She had committed herself now;
>  recklessly she plunged on.
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> 1954 Times Lit. Suppl. 12 Nov. 714/4 As the Age of Reason plunged
>  towards revolution, Juvenal was carried like a banner in the van of
>  the attack.
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> 
> 1990 A. Stevens On Jung ii. 18 The dreamer might see a train,
>  carrying him home, plunging in and out of a series of tunnels.
> 
> 
> 2004 Derby Evening Tel. (Nexis) 16 Mar. 6 If the Germans had
>  captured crossings over the Trent, they could have plunged in any
>  direction.
> 
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"Plunged" is a good word to use, but "sunlight" would be much better then "sun". 

Otherwise, you could say "emerged" into the sunlight. 

One historical example shows both "plunged" and "emerged" would be good choices: 

[Reports of Observations of the Total Eclipse of the Sun, August 7, 1869](https://books.google.com/books?id=c00QPyT2IjMC&pg=PA108&lpg=PA108&dq=%22plunged%20into%20%22%20sunlight&source=bl&ots=WqTGBpgo99&sig=zznbtkA2vX7fQjSBLuwgE1CF9vY&hl=en&sa=X&ved=0ahUKEwjT0aK25vvTAhUF6yYKHaqOBnkQ6AEIUTAI#v=onepage&q=%22plunged%20into%20%22%20sunlight&f=false):

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> ...observed with what frightful rapidity we were plunged into the dark shadow, and the contrary effect as we emerged into sunlight
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