I feel like I'm missing something, because it looks like it covers all of these:

• "southwest" of center,
• "northeast" of center,
• "northwest" of center, and
• "southeast" of center, respectively.

What it doesn't capture is chemist & zoologist only and government & dermatologist only. (4c4 is 1, covered; 4c3 is 4, all covered, and 4c1 is obviously 4, also covered, but 4c2 is 6, and only 4 are covered.)