Answer:
Bang! Something hit the wall outside Peter’s room.
Step-by-step explanation:
An exclamation mark, ! , is used to expressed a sudden surge of emotion. The emotions range from happiness to surprise, shock, anger, pain, etc. An exclamation when used with an interjectory remark can capture a reader's attention as it connotes the feeling of suddenness.
Just as the sound Bang! can conjure sudden attention in the real world, so does it also get a reader's attention quickly.