Actually Revit API supported to do that with method IsPointInRoom :
But you can try with orignal node in OpenMEP package 
in case use with complex purpose
https://chuongmep.github.io/OpenMEP/api/OpenMEPSandbox.Geometry.Point.html#OpenMEPSandbox_Geometry_Point_IsInPolygonPlus_Autodesk_DesignScript_Geometry_Point_Autodesk_DesignScript_Geometry_Polygon_
