It is possible to run Universal AV real-time protection along with other traditional antivirus, but you are right, double reading will happen if both are trying to scan the same file. On our side, to allow this to happen, we set the file reading permission to be shared, so other antivirus can read the same file at the same time. Usually the same thing is done by other antivirus company, if they are reading the file first, they also will share the file reading permission, so other process can read the same file while the scanning occurs.