Why does the sentry lead Antigone into presence on his second visit in

The sentry leads Antigone into presence on his second visit because he is carrying out the orders of Creon. Creon had ordered the sentry to arrest anyone who was caught burying Polynices, and Antigone had been caught in the act. The sentry is therefore obligated to take Antigone to Creon, so that she can be punished for her crime.