Subway is not horribly bad, nor is it horribly expensive, so that’s usually my default.
Taco Bell
Baja Beef Gorditas are amazing.
As are Beefy 5-Layer Borritos
If we are talking burgers, all things being equal, I would choose Wendy’s.
My fastfood choices are almost always Wendy’s Double Stack Value Meal ($3.28 with tax) or a Chick-fil-A 6 nugget kid’s meal. When I’m done I trade in the toy or book for a small ice cream.
StG
I don’t like fast food hamburgers. Actually I tend not to like anything at fast food burger places - I can find something if, for example, my dad insists on Carls Jr.
If I can find one, I’ll generally choose Baja Fresh, otherwise Subway (mostly for the cookies 
) or a Chinese Place. If non of those are available, Taco Bell.
If Taco Bell or KFC is an option, I’ll get that. Barring that, McDonald’s will do it for me.
If we’re talking about the actual food courts that I visit, then Panda Express, Indian food, or Boston Chowda Company are what I’ll get.
I don’t know what’s to eat in the mall, but I do like several things on the McDonald’s menu. I haven’t eaten there since the good old days when mice had balls, but I’m willing.
Wendy’s is my go-to when it is available. Their spicy chicken sandwich is so good! If that isn’t available Taco Bell or a slice of pizza work just fine for me.
Chipotle.