Pausing is a bad idea.
You start the scan, pause it and do some things on the system.
That means things on the part that already was scanned can have changed and need to be scanned again.
This will make the scan take much longer.
If the scan just continues where it left off, there is a change a detection is missed.
Just run the scan when you don't need the computer.
e.g. when you go to sleep, get groceries etc.