Hello Legit,
You cannot do this..!!..This is also not recommended...If you want to turn off realtime scanner then it can only be set permanently off..McAfee home products do not have exclusion option, enterprise product do have it..!! But what McAfee does is logical and good..otherwise if something goes wrong like system unstable or unusual behavior then people will blame McAfee...You can send that file to McAfee for analysis and also check which scanner detects it. like on virus total and threat expert, atleast on threatexpert you can check it's behavior..