RESCUE breathing aka mouth-to-mouth resuscitation.
To be honest, Zoe wasn't sure if Isaak needed that.
But she couldn't just do nothing while her husband stopped breathing just in front of her! She tried chest compressions earlier, but they didn't work. So, now, she decided to try CPR.
She wasn't that confident since she hadn't given anyone CPR before.
Her knowledge of CPR only came from the medical Kdramas that she had binge-watched in the past.
[This mouth is only good at kissing Isaak.]
She still had to try, though.
[Here we go, yeobo.]
She placed one hand on Isaak's forehead, then she used her other hand to lift his chin. She tilted his chin to straighten the trachea (aka the windpipe), providing a straight passage from the mouth to the lungs.
Then she began the mouth-to-mouth resuscitation.