Раз уж мы уже в вестибюле, давай купим воду и спокойно подождём.

Раз уж is a set expression meaning something like:

• since
• given that
• seeing that
• now that

It often adds a nuance of “well, since that’s already the case...” or “given the situation...”.

So in this sentence, Раз уж мы уже в вестибюле... sounds like:

• Since we’re already in the lobby...
• Well, now that we’re already in the lobby...

A quick comparison:

• раз by itself can mean since in colloquial Russian
• уж often adds emphasis, resignation, or “as things stand”
• раз уж together is very natural and common in spoken Russian

It has a slightly conversational tone.

It may look repetitive, but these are doing different jobs.

• In раз уж, the word уж is part of a fixed expression.
• The second уже is the normal adverb already.

So:

• раз уж = since / now that
• уже = already

That means Раз уж мы уже в вестибюле... literally feels like:

• Since we’re already in the lobby...

Even though English also repeats similar ideas sometimes, in Russian this is perfectly natural.

В вестибюле uses the prepositional case because it expresses location:

• в
  • prepositional = in / inside / at a place

Base form:

• вестибюль = lobby / vestibule

Prepositional singular:

• в вестибюле = in the lobby

This is a common pattern:

• в доме = in the house
• в магазине = in the store
• в метро = in the metro

If it were motion into the lobby, Russian would use the accusative:

• в вестибюль = into the lobby

But here the meaning is static location, so в вестибюле is correct.

Yes, Russian often drops subject pronouns when they are clear from the verb. So you could say:

• Раз уж уже в вестибюле...
• or more naturally, you would usually keep something to avoid awkwardness, but in some contexts the pronoun may be omitted.

However, мы is very natural here because it keeps the sentence clear and balanced:

• Раз уж мы уже в вестибюле, давай...

Including мы can make the sentence sound a bit more explicit and conversational. Russian does not have to omit pronouns; it just often can.

Here давай is used to make a suggestion, like:

• let’s
• come on, let’s

So:

• давай купим воду = let’s buy water

This is a very common spoken pattern:

• давай пойдём = let’s go
• давай посмотрим = let’s have a look
• давай подождём = let’s wait

A few important points:

1. Давай literally comes from давать (to give), but here it does not mean give.
2. It is conversational and very common in speech.

3. With мы, another way to express let’s is the 1st person plural future/form alone:

   • купим воду и подождём This can also mean we’ll buy water and wait, depending on context.

   Adding давай makes it clearly a suggestion.

Купим is the 1st person plural perfective form of купить (to buy).

Here it is used because the speaker suggests a single completed action:

• let’s buy (some) water

Why not покупаем?

• покупаем is imperfective, present tense, and usually means we are buying or sometimes let’s buy only in very specific contexts
• it would not sound as natural here for a simple suggestion of one completed purchase

Why not infinitive покупать?

After давай, Russian usually uses a finite verb, very often a 1st person plural form:

• давай купим
• давай подождём

So the aspect choice makes sense:

• купим = complete the purchase
• подождём = wait for a while / through a period

Because вода is the direct object of купим, it goes in the accusative case.

Base form:

• вода = water

Accusative singular:

• воду

So:

• купить воду = to buy water

This is standard for a feminine noun ending in -а:

• книга → книгу
• машина → машину
• вода → воду

Подождём is the 1st person plural perfective form of подождать.

It means:

• we’ll wait
• in this context, with давай, let’s wait

Why perfective?

Because the speaker means wait for a while until something happens, treating it as a bounded action. Russian often uses подождать when the waiting is seen as a complete stretch of time.

Compare:

• ждать = to wait, be waiting (more general, ongoing)
• подождать = to wait a bit / wait for some time / wait until something

So спокойно подождём means something like:

• let’s wait calmly
• let’s just wait quietly for a bit

Спокойно is an adverb here.

It describes how they will wait:

• подождём как? → спокойно
• wait how? → calmly / peacefully / without rushing

Compare:

• спокойный = calm (adjective, used with nouns)
• спокойно = calmly / calmly enough / in a calm way (adverb)

Examples:

• спокойный человек = a calm person
• говорить спокойно = to speak calmly
• спокойно подождём = we’ll wait calmly

In this sentence it suggests not hurrying or stressing.

Because both verbs depend on давай, which is making a suggestion for us to do something.

So Russian uses 1st person plural forms:

• давай купим
• и подождём

The second verb doesn’t need another давай because it continues the same idea:

• Let’s buy water and wait calmly.

This is very natural coordination in Russian.

Russian word order is flexible, but the original order sounds natural and smooth.

Original:

• Раз уж мы уже в вестибюле, давай купим воду и спокойно подождём.

This order works well because it goes:

1. reason/background
2. suggestion
3. two actions

You can move some words for emphasis, for example:

• Раз уж мы в вестибюле уже, давай купим воду...
  This is possible, but less natural in neutral speech.

• Давай, раз уж мы уже в вестибюле, купим воду и спокойно подождём.
  Also possible; this puts focus on the suggestion first.

So yes, word order can change, but the original is a very normal default.

Because the first part is a subordinate clause giving the reason or situation:

• Раз уж мы уже в вестибюле, ...
• Since we’re already in the lobby, ...

Russian normally separates this kind of introductory subordinate clause from the main clause with a comma.

So:

• Раз уж мы уже в вестибюле = subordinate clause
• давай купим воду и спокойно подождём = main clause

That comma is required.

The correct pronunciation is with ё:

• подождём

In many printed texts, Russian often writes е instead of ё, so you may also see:

• подождем

But the pronunciation and meaning are the same, and in careful learning materials ё is often shown to help learners.

So:

• подождём = clearer for learners
• подождем = common in everyday writing

In many real-life contexts, вестибюль is best translated as:

• lobby
• entrance hall
• foyer

Although it is related to the English word vestibule, the natural English translation often depends on the building:

• station → lobby / entrance hall
• theater → foyer
• large building → lobby

So learners should not always translate it mechanically as vestibule in English, even though that is the dictionary-relative word.