I booked a shared room but the existing resident started threatening me as soon as I entered the room. I immediately came out of the property and contacted host. I waited for him to respond for some time before I contacted airbnb. While I was on call with airbnb, host called me up and I explained him the whole situation. Host offered me to refund the whole reservation money and assured me that he will speak to the existing guest.
My suggestion- Spend little more money but avoid shared room if possible.