What's a word for saying 'entering a room suddenly and fast'?
Burst
Definition #2 from Collins English Dictionary:
(intr) to come, go, etc., suddenly and forcibly. He burst into the room.
Barge
Definition #2 (verb) from Merriam-Webster Dicitonary:
(intr) to thrust oneself heedlessly or unceremoniously. She barged through the door without even knocking
Consider also storm, from the Free Dictionary:
To move or rush tumultuously, violently, or angrily: stormed into the room.
While I was making it up as a joke, @Callithumpian has encouraged me to offer "Kramering" as a real answer. Here is a definition from the Urban Dictionary, and here is a visual explanation of the origin of the term.
Rush from the Free Dictionary:
- To make a sudden or swift attack or charge.
Example: “He rushed into the room to break the bad news.”