There was certainly enough circumstantial evidence to warrant a search and seizure of the Ajou University Pediatric ER.

Looking at the news articles, even if you set aside the baby's side's claims, the hospital's own records show that at the time the baby entered the ER, the oxygen saturation was 80% and it was an emergency situation where it dropped to 50% within 5 minutes.
Despite this, it is reported that the hospital sent the interpreter away, which is incomprehensible from a common-sense perspective.
Since an autopsy has already been performed, a conclusion will likely be reached once they check for any pre-existing medical conditions, but even accounting for potential miscommunication involving a foreigner's interpretation, it is truly baffling that they sent the interpreter away during an emergency where a baby's life was at stake.
Even if that didn't actually happen, from the perspective of the family, the police, and the judge who received the reports, one cannot ignore the possibility that the hospital might have caused an accident and tried to cover it up.
In that case, the police's approach—searching the non-treatment areas for less than 30 minutes and then waiting for the current patients' treatments to finish before searching the remaining areas—can only be described as a sufficiently rational approach.
It seems like the doctors are once again playing the victim and whining about how they are dying.