If you believe there’s immediate danger to a child (or an adult), you should call the police and let the police intervene. Do not put yourself in danger because you don’t know what will happen after your neighbor opens their door.
The information in this answer is general in nature and is not legal or insurance advice for your specific situation. Policy language varies carrier by carrier; your declarations page is the final word. If you're unsure, call your agent before you need to file.