teidensite erebeetaa ga tomattara, mazu otituite tasuke wo mateba ii.

停電 is a noun meaning power outage, but it can also act like a する-verb: 停電する = to have a power outage / for the power to go out.

So 停電して is the て-form of 停電する. Here it connects this event to the next part of the sentence:

停電して エレベーターが止まったら
= if the power goes out and the elevator stops
or more naturally, if the elevator stops because of a power outage.

Only the second part, 止まったら, carries the main if/when meaning.

Japanese often uses the て-form to connect one event to another, and then puts the conditional on the final event:

停電して エレベーターが止まったら
literally: if, after a power outage happens, the elevator stops...

This makes the power outage feel like the background or cause, and the elevator stopping is the condition the speaker is focusing on.

が marks エレベーター as the subject of 止まる: the elevator is the thing that stops.

In a conditional clause like this, が is very natural because it introduces the event straightforwardly:
if the elevator stops...

Using は would sound more contrastive or topic-like, as if you were setting the elevator apart from something else. In this sentence, が is the normal choice.

This is a very common Japanese pattern.

The たら conditional is formed with the past plain form:

• 止まる → 止まった
• 止まったら = if/when it stops

So the past-looking form here does not mean past time. It is just how the たら conditional is built.

止まる means to stop and is an intransitive verb.

That matters because the elevator stops by itself or comes to a stop. You are not saying someone stopped it. If you wanted a transitive verb, you would use something like 止める = to stop something.

So:

• エレベーターが止まる = the elevator stops
• エレベーターを止める = someone stops the elevator

まず means first or first of all.

It shows priority: before anything else, the person should calm down. In emergency instructions, まず is very common because it signals the first recommended action.

落ち着いて is the て-form of 落ち着く, which means to calm down or to become calm.

In this sentence it means something like:

• calm down and...
• stay calm and...

So まず 落ち着いて 助けを待てばいい means first, calm down and wait for help.

It can suggest both, but in this sentence the strongest feeling is calm down and then wait.

Because of まず, the sentence sounds like a sequence of advice:

1. calm down
2. wait for help

At the same time, it also gives the nuance of waiting in a calm state.

助け is a noun meaning help, assistance, or even rescue depending on context.

So 助けを待つ means to wait for help. The particle を marks 助け as the object of 待つ.

This is natural Japanese in an emergency context. It does not mean wait and then help; it means wait for rescuers/help to come.

待てばいい comes from:

• 待つ = to wait
• 待てば = if you wait
• いい = good

So literally it means it is good if you wait. In natural English, that usually becomes:

• you should wait
• just wait
• the best thing to do is wait

This pattern, 〜ばいい, is a common way to give advice.

Yes. 待てばいい is softer and more advisory than something like:

• 待て = wait! very direct
• 待ちなさい = stronger instruction
• 待ってください = please wait

待てばいい sounds more like calm guidance: you should wait or it's best to wait. That fits the reassuring tone of this sentence.

The subject is omitted because it is obvious from context.

Japanese often leaves out pronouns when they can be understood. In a warning or instruction like this, the implied subject is you:

If the power goes out and the elevator stops, first calm down and wait for help.

Yes. The sentence does not force a very narrow logical relationship.

停電して can simply connect the two events in sequence, but in real context it strongly suggests that the elevator stopping is related to the power outage. So natural English often makes that connection explicit:

If the elevator stops because of a power outage...

Both ways of understanding it are close, but the practical meaning is the same.

Ending with いい makes the sentence sound more like practical advice than a harsh order.

In emergency guidance, this can feel calmer and more reassuring. Instead of barking a command, the speaker is telling you the appropriate thing to do:

First, stay calm. Waiting for help is the right response.