A B757-200 flight crew reported two flight attendants had minor injuries after a sudden stop to avoid another taxiing aircraft.

Narrative

While taxiing out we were told to then follow a [regional turboprop] that was taxiing out behind us. I noticed the [regional turboprop] taxi rapidly by us shortly after that. While doing the Before Takeoff Checklist I was looking down and responding to the checklist for 'trim setting' when the Ground Controller told us to hold our position. I immediately looked up and saw the [regional turboprop] starting to turn in front of us on; so I stopped abruptly. The [regional turboprop] then continued taxiing ahead of us for an intersection takeoff and we continued on for the full length of runway behind the [regional turboprop]. I had thought that the [regional turboprop] was turning on another taxiway further ahead. I assumed all was well as several minutes elapsed before our takeoff. Sometime later in the climb the Purser called and let me know that two of the flight attendants had fallen down or hit the door by the cockpit; but that they were okay and could continue the flight in their duties but that they wanted to let me know that they had fallen or hit something during our rapid stop while taxiing. I heard no particularly unusual noises from the cabin during taxi. The flight continued uneventfully.