Effect of door opening and revealing light

Can anyone help me find an effect that looks like a door opening in a dark room and shining light on a character?
Like, you see the characters face in a dark room and they are facing a closed door. Someone opens the door letting light from the hallway in. The light shines on the character. Or if you can help me come up with an effect similar to this.
The point is that I have characters hiding from a killer and the killer finds them in this dark room.

Thank you!

What’s that?

I can’t find a Diamond Workshop. Are you sure its still called that?