Спасатель сказал, что во время пожара лучше не пользоваться лифтом.

Because спасатель is a masculine noun here, so the past-tense verb agrees with it in gender.

• спасатель = rescuer / firefighter / rescue worker
• сказал = said (masculine singular)
• If the speaker were female, it would be сказала.

In Russian past tense, singular verbs show gender:

• сказал = he said
• сказала = she said
• сказало = it said
• сказали = they said

Что here means that and introduces a subordinate clause.

So the structure is:

• Спасатель сказал = The rescuer said
• что ... = that ...

This is very common in Russian:

• Он сказал, что придёт. = He said that he would come.
• Я знаю, что это важно. = I know that this is important.

Because Russian normally uses a comma before a subordinate clause introduced by что.

So:

• Спасатель сказал, что...

This is standard Russian punctuation. In English, that is sometimes omitted, but in Russian the comma is still required when the clause is present.

Во время means during.

It requires the genitive case, so пожар changes to пожара.

• dictionary form: пожар = fire
• after во время: пожара = during the fire

This pattern is regular:

• во время урока = during the lesson
• во время войны = during the war
• во время поездки = during the trip

Russian uses во instead of в before some consonant clusters to make pronunciation easier.

So you say:

• во время
• not в время

This is a pronunciation-driven variant of the preposition в.

Other examples:

• во Франции
• во вторник

Yes. Лучше не + infinitive is a very common Russian pattern meaning:

• it’s better not to ...
• you’d better not ...

So:

• лучше не пользоваться лифтом = it’s better not to use the elevator

Other examples:

• Лучше не спешить. = It’s better not to hurry.
• Лучше не спорить. = It’s better not to argue.

This structure often gives advice in a general, impersonal way.

Because пользоваться requires the instrumental case.

So:

• dictionary form: лифт
• instrumental singular: лифтом

That is why the sentence has:

• пользоваться лифтом

This is an important verb pattern to memorize:

• пользоваться телефоном = to use a phone
• пользоваться словарём = to use a dictionary
• пользоваться компьютером = to use a computer

Both can often translate as to use, but they behave differently.

пользоваться

• often means make use of / use regularly / use as a means
• takes the instrumental case
• very natural with things like transport, tools, services

Examples:

• пользоваться лифтом = use the elevator
• пользоваться интернетом = use the internet

использовать

• more like utilize
• takes the accusative case
• often sounds more direct, technical, or formal

Example:

• использовать лифт

In this sentence, пользоваться лифтом sounds very natural.

Because it depends on лучше in the pattern лучше не + infinitive.

The sentence is not saying:

• do not use the elevator as a direct command

Instead, it gives general advice:

• it is better not to use the elevator

That is why the infinitive is used.

Yes, Russian word order is flexible, but the original order is natural and neutral.

The sentence is:

• Спасатель сказал, что во время пожара лучше не пользоваться лифтом.

This flows nicely from:

1. who spoke
2. what was said
3. when the advice applies
4. the advice itself

You could move parts around for emphasis, for example:

• Спасатель сказал, что лучше не пользоваться лифтом во время пожара.

This is also correct and means almost the same thing. The difference is mainly emphasis and rhythm.

Because the sentence is talking about a fire / a fire situation in general, not multiple fires.

• во время пожара = during a fire / during the fire

Russian often uses the singular in general safety statements like this.

If you used the plural, во время пожаров, it would mean during fires in a broader, repeated sense, which is less natural here.

Yes. Лифт is a masculine noun.

That is why its forms look like this:

• nominative: лифт
• genitive: лифта
• dative: лифту
• accusative: лифт
• instrumental: лифтом
• prepositional: лифте

In this sentence, you see the instrumental form лифтом because of пользоваться.

Yes, but the meaning would become stronger.

лучше не пользоваться лифтом

= it’s better not to use the elevator

• advice
• recommendation

нельзя пользоваться лифтом

= you must not use the elevator / it is forbidden to use the elevator

• stronger rule
• prohibition

So the original sentence sounds like advice from a rescuer, while нельзя would sound more like a strict safety rule.