uisaneun jeungsangi simhaejimyeon eunggeupsillo baro orago haesseo.

는 marks 의사 as the topic: as for the doctor...

In this sentence, the doctor is probably already known in the conversation, so 의사는 sounds natural. It can also carry a slight contrastive feel, like the doctor said...

If you said 의사가, it would sound more like you are newly identifying the doctor as the subject or focusing on who said it.

So:

• 의사는 = as for the doctor / the doctor, speaking of them
• 의사가 = the doctor did it / it was the doctor who did it

Both can work in context, but 의사는 is very natural here.

In 증상이 심해지면, 증상 is the subject of 심해지다.

So the structure is basically:

• 증상이 = the symptoms
• 심해지면 = if they get worse / become more severe

Using 이/가 here is the most neutral way to mark the subject of the condition.

If you said 증상은 심해지면, it would sound more contrastive or topical, as if you were setting the symptoms apart from something else. That is possible in some contexts, but 증상이 is the normal choice here.

심해지면 breaks down like this:

• 심하다 = to be severe
• -아/어지다 = to become
• -면 = if / when

So:

• 심하다 → 심해지다 = to become severe, to get worse
• 심해지면 = if it gets worse / when it gets worse

This is a very common pattern in Korean:

• 좋아지다 = to get better
• 나빠지다 = to get worse
• 커지다 = to become bigger

So 증상이 심해지면 is literally if the symptoms become severe.

This is an important nuance.

• 심하면 = if it is severe
• 심해지면 = if it becomes severe / gets worse

So 심하면 describes a state, while 심해지면 describes a change.

In a medical sentence about symptoms, 심해지면 is very natural because it suggests that the symptoms may worsen over time.

Compare:

• 증상이 심하면 = if the symptoms are severe
• 증상이 심해지면 = if the symptoms get worse

Yes, 응급실에 could also be possible.

With motion verbs like 가다 and 오다:

• 에 often marks the destination
• 로 often emphasizes direction or movement toward a place

So:

• 응급실에 오다 = come to the ER
• 응급실로 오다 = come toward/to the ER

In practice, both can be natural. 로 can feel a little more directional, and in urgent instructions like this, it sounds very natural.

So 응급실로 바로 오라고 했어 has a strong head straight to the ER feeling.

오라고 했어 is reported speech for a command or instruction.

It uses the pattern:

• verb stem + -(으)라고 하다 = to say/tell someone to do something

Since 오다 has a vowel-ending stem 오-, you use -라고:

• 오다 → 오라고 하다

Examples:

• 가라고 했어 = said to go
• 먹으라고 했어 = said to eat
• 기다리라고 했어 = said to wait

So 오라고 했어 means said to come or told me/us/him/her to come.

Because this grammar attaches to the verb stem, not to the everyday imperative form.

The verb is 오다, and its stem is 오-. So:

• 오- + 라고 → 오라고

Even though the direct command form is often 와! or 와라, reported commands use the stem-based pattern -(으)라고 하다.

So the correct form is:

• 오라고 했어

not

• 와라고 했어

Korean chooses come vs. go based on perspective.

Here, the doctor is telling the patient to come to the ER from the doctor's point of view, or from the point of view of the destination. So 오다 is natural.

You can think of it as:

• from the patient's perspective: go
• from the doctor's/hospital's perspective: come

So 응급실로 바로 오라고 했어 is like The doctor said to come straight to the ER.

In another context, 가라고 했어 might also be possible, but this sentence is framed from the doctor's side.

That person is omitted because Korean often leaves out information that is obvious from context.

The full idea could be something like:

• 의사는 나한테 응급실로 바로 오라고 했어
• 의사는 환자한테 응급실로 바로 오라고 했어

In English, we often need to specify me, him, the patient, and so on. In Korean, if it is clear, it can be dropped.

So in this sentence:

• the doctor = the person who said it
• the patient/listener = the person who should come

바로 means right away, immediately, or sometimes directly.

Here it adds urgency:

• 응급실로 오라고 했어 = said to come to the ER
• 응급실로 바로 오라고 했어 = said to come to the ER right away

So it makes the instruction feel more urgent and immediate.

했어 is informal, casual speech.

It is the casual past form of 하다. So the whole sentence sounds like something you would say to:

• a friend
• a family member
• someone younger
• yourself in casual narration

More polite versions could be:

• 의사는 증상이 심해지면 응급실로 바로 오라고 했어요.
• 의사는 증상이 심해지면 응급실로 바로 오라고 했습니다.

So the grammar is the same, but 했어 tells you the speaker is using a casual style.