Creating a Door that can be open only after multiple requirements are met can be a bit complicated at first.

I first created a button that could be pressed and turned to true to trigger the door to open nothing too complicated. but then adding the new factor like killing a specific enemy or killing a hoard of enemies that spawn, or giving the ability to the door to open but close the door when more enemies spawn is the type of door I wanted to create. 

I managed to do this by creating an interface that would return a boolean and adding that boolean to all the actors that could affect the door