I'm afraid you don't have a lot of options inside security at BWI's "C" pier.

Your best bet there may be a Nathan's hot dog.

Really.

You can visit the all-Southwest "B" concourse without leaving the secured area (with only a two hour stay that's probably what I'd suggest) and there's somewhat better food options, including a place that makes deli sandwiches, but BWI's not a place to visit for fine dining, especially inside security.