Most of the best sandwiches I’ve had in my short life have come from unseemly holes-in-the-wall—you know, the kind you might think twice about due to dodgy health code reputations, surly counter people, or lack of clear signage and visible, glowing reviews from newspaper “Best Ofs.” The Sentinel, however, is pedigreed and neat as a pin—and its excellent, $8-$9 sandwiches are garnering top marks all around. ~ By Nirmala Nataraj