Ten, kto zobaczy płomień albo poczuje dym, powinien najpierw powiedzieć innym, a potem spokojnie wyjść.

Ten, kto ... is a common Polish structure meaning the one who ..., whoever ..., or anyone who ....

So:

• Ten = that one / the one
• kto = who

Together, Ten, kto zobaczy... means something like Whoever sees... or The person who sees...

In English, we usually would not translate ten literally as that one here. It is just part of a natural Polish pattern.

You can also sometimes see a simpler version without ten:

• Kto zobaczy płomień..., powinien...

That also works, but ten, kto sounds a bit more formal and structured.

Kto means who and is used for people.

Here it refers to a person:

• Ten, kto zobaczy płomień... = The person who sees the flame...

Why not the others?

• który usually means which or who in a more specific relative clause, often after a noun:
  • osoba, która zobaczy płomień = the person who sees the flame
• co usually means what, or in some informal contexts that/which, but not here

So kto is the natural choice in this kind of general statement about a person.

This is a very common point of confusion.

zobaczy comes from zobaczyć and poczuje from poczuć. These are perfective verbs. In Polish, perfective verbs do not have a normal present tense. Their present-looking forms usually refer to a future completed event.

So:

• zobaczy = will see
• poczuje = will feel / will smell depending on context

But in sentences like this, Polish often uses these forms in a general condition:

• Ten, kto zobaczy płomień albo poczuje dym...
• literally: Whoever will see a flame or will smell smoke...
• natural English: Anyone who sees a flame or smells smoke...

So although the form is future-like, the whole sentence expresses a general rule.

Because the sentence refers to a single event happening, not an ongoing state.

Compare:

• zobaczy płomień = catches sight of / sees a flame (at some moment)
• poczuje dym = notices / smells smoke (at some moment)

These are one-time trigger events. That is why perfective verbs fit well.

If you used imperfective forms like:

• widzi płomień
• czuje dym

it would sound more like describing an ongoing situation rather than the moment of noticing something.

In emergency instructions, Polish often prefers perfective verbs for this kind of if someone notices X, they should do Y meaning.

Both nouns are in the accusative case, because they are direct objects:

• zobaczy płomień = sees a flame
• poczuje dym = smells smoke

But Polish noun forms do not always visibly change in the accusative.

płomień

This masculine noun changes form in the accusative singular:

• nominative: płomień
• accusative: płomień

Actually, in this case it looks the same in writing, but grammatically it is accusative.

dym

This is also masculine inanimate, and masculine inanimate nouns often have accusative identical to nominative:

• nominative: dym
• accusative: dym

So dym does not visibly change.

The main point: both are objects, and both are functioning in the accusative, even if the forms look unchanged.

Not usually in natural English.

Although poczuć often means to feel, with things like smells it can mean to smell, to sense, or to notice.

So:

• poczuć dym = to smell smoke
• not usually to feel smoke

This is a vocabulary point: Polish czuć / poczuć covers a wider range than English feel.

Other examples:

• czuję ból = I feel pain
• czuję zapach kawy = I smell coffee
• poczułem chłód = I felt a chill

Both albo and lub can mean or.

In this sentence:

• płomień albo poczuje dym = a flame or smells smoke

albo is very natural in everyday language.
lub is also correct, but it can sound a little more formal or neutral, depending on context.

In many sentences they are interchangeable:

• kawa albo herbata
• kawa lub herbata

Both mean coffee or tea.

Here, albo sounds perfectly natural.

Powinien is singular masculine, and here it is being used in a generic sense: the person who... should...

This is common in Polish when talking about an unspecified person in a rule or instruction.

So:

• Ten, kto zobaczy..., powinien...

means Whoever sees..., should...

Even though in real life the person could be male or female, Polish often uses the masculine singular as the default in general statements.

If you wanted to avoid that, you could rephrase the sentence, for example with osoba:

• Osoba, która zobaczy płomień albo poczuje dym, powinna...

Now powinna agrees with osoba, which is feminine grammatically.

Innym is in the dative plural.

The verb powiedzieć often works like this:

• powiedzieć komuś coś = to tell someone something

So here:

• powiedzieć innym = tell others
• literally: tell to others

The base word is inni = others.
Its dative plural form is innym.

Examples:

• powiedzieć kolegom = tell friends / tell the colleagues
• powiedzieć dzieciom = tell the children
• powiedzieć innym = tell others

This is about aspect again.

• powiedzieć = perfective = to say / to tell once, successfully
• mówić = imperfective = to speak / to say repeatedly / to be saying

In this sentence, the person is supposed to perform a specific action:

• first, tell others
• then, leave calmly

That is why powiedzieć fits better: it presents the action as a single completed step.

If you used mówić, it would sound less natural here because the instruction is about a one-time action, not ongoing speech.

Because spokojnie is an adverb, and it describes how the person should leave.

• spokojnie = calmly
• spokojny / spokojna = calm as an adjective describing a noun

Here it modifies the verb wyjść:

• spokojnie wyjść = to leave calmly

Compare:

• spokojny człowiek = a calm person
• człowiek wyszedł spokojnie = the person left calmly

So the sentence needs the adverb spokojnie.

Again, this is perfective vs. imperfective.

• wyjść = perfective = to go out / leave as a completed action
• wychodzić = imperfective = to be leaving / to leave habitually / to go out repeatedly

In an instruction like this, Polish prefers the perfective form because it refers to a specific action that should be completed:

• a potem spokojnie wyjść = and then leave calmly

It is one clear step in the sequence.

This pair marks the order of actions very clearly:

• najpierw = first
• a potem = and then / then

So the sentence gives a sequence:

1. najpierw powiedzieć innym = first tell others
2. a potem spokojnie wyjść = and then leave calmly

The a here is a very common connector meaning something like and or and then. It helps link the second step to the first one.

Because kto zobaczy płomień albo poczuje dym is a subordinate clause inserted after ten.

The structure is:

• Ten, kto zobaczy płomień albo poczuje dym, powinien...

This is similar to:

• The one who sees a flame or smells smoke should...

Polish punctuation normally separates that inserted clause with commas.

So the commas help show the sentence structure:

• Ten = main pointing word
• kto zobaczy... = clause explaining which person
• powinien... = main statement

Yes, to some extent. Polish word order is more flexible than English, though not completely free.

The original order is natural and clear:

• Ten, kto zobaczy płomień albo poczuje dym, powinien najpierw powiedzieć innym, a potem spokojnie wyjść.

You could rephrase parts of it, for example:

• Ten, kto zobaczy płomień albo poczuje dym, powinien powiedzieć najpierw innym, a potem spokojnie wyjść.

This is understandable, but the original sounds better because najpierw naturally introduces the first action before the infinitive phrase.

In short: yes, some movement is possible, but the original order is the most idiomatic for a clear instruction.