She is a prison guard. Think about what that job involves for a moment.
Back in the third century when Christians came to make up a large part of the population in the Roman Empire they had to resolve the issue of whether Christians could participate in temporal government. The line taken by Augustine, and others, was that peace and order are necessary conditions for the preservation and propagation of Christianity itself, so Christians are allowed fill those roles required for the maintenance of peace and order. You can think of this as a sort of religious 'necessary and proper' clause. If God tells you to do X, but X requires Y, then it must be OK to do Y.
Some modern Christians belong to sects that reject this view, and insist that Christians should remain separate from all worldly government, but they are a very small minority. The vast majority have had no problem with exercising temporal power, i.e. "telling other people what to do", for more than one and a half millennia.