it also depends on which Shaw entrance you walk to, the one at 8th and R is a lot more dangerous and "in the cut" than the one further up north. You'd be safer catching the bus to the metro station, the #80 bus stop is like a block away from 1st and S and goes to Union station and Brookland-CUA, the #G8 also comes a block away on 1st and Rhode Island, you can catch that to Shaw Howard and Brookland-CUA. Visit
Metro - Home page for more info on the bus routes.