Roast beef, four to six slices depending upon thickness, and two slices of provolone cheese.
The Mayo and the mustard are mixed in an 80/20 composition, and the garlic is sprinkled over it.
Then it is smeared over the layers before the sandwich halves are slapped together.
No wonder the bags melt...that's too much sandwich for a regular sandwich bag...you need a quart-size freezer bag!
RB and provolone is excellent. Are you using crushed garlic spread?
You intimated that you couldn't cook. That sounds like a heck of a sandwich to me.