Luke heard the crash from inside the room, but he was still caught off guard by the door blasting outward and hitting the wall. He sent a Force wave of his own toward it to stop it hitting him and push it aside. He drew his lightsaber, worried about what he might run into or what might come bursting out.
He reached out in the Force, trying to figure out if he could sense anything. A Force user could certainly cause damage like that without much effort. However, he didn't feel any Force presence here. Whoever it was, they were something different.
Cautiously, he looked into the doorway but didn't enter, not wanting to risk anything until he knew what he might be up against. He did sense anger and fear, and though he kept the cylindrical hilt of his weapon in his hand, he hesitated to ignite it just yet.
"It's all right..." he called out. "I don't mean you any harm..."