Using molotovs to kill the group of enemies in the first hallway is much faster than using the Ingrams or any other weapon. You need to roll through the hallway the way I did to avoid the enemies blocking you, and you need to wait to throw the molotov down next to the last enemy in the hallway holding the Ingrams to be able to kill all of them. I also realized that it was better to switch to the grenades during the Vinnie cutscene at the end. If you do it fast enough at the beginning of that cutscene, you don't lose any time.