Two women who got out of a burning car on the Q bridge were injured Thursday night when a car drove into a pick-up truck behind the car, pinning them, police said. Emma S. Carmichael, 26, of Brattleboro, Vt., and Milly C. Johnsen, 27, of Kingston, R.I. both suffered serious injuries to their lower extremities and were transported to Yale-New Haven Hospital, state police said. They were conscious and alert at the time, they said. A third person who had stopped a Ford F 450 pick-up truck to help them also was transported, police said.