Actually, all AA terminals are connected via a trAAin that is inside security. Therefore, A, B and C connections do not require that you go downstairs to the ground level and "look behind you". The trAAin is available across from C27, C16, A30-something, A15 and B5. Just follow the signs.

If you don't like the trAAin and don't mind the stroll, you can go from the farthest end of A (A1) or C (C37) and walk all the way to B in about 15 minutes or so (depending on traffic ) There are moving walkways between all three terminals. The terminals all meet "in the middle" at A39/C1/B5.