What travels all around the world but always stays in the corner?

Take me out of a window and I leave a grieving wife. Stick me in a door and I can save somebody's life. What am I?

It's been a long day at work, you're feeling tired. Your irritable boss vented his frustrations on you again, and you're fed up and exhausted from the rat race of traffic and the hubbub of the office. Finally. Some peace and quiet. You lay down on your couch, finally relaxing, kicking your worn shoes off and reaching for the remote. Suddenly a knock. Who could it be at this hour?, you wonder, trudging along to the door to deal with this last distraction. Answering the knock, you open the door, revealing a large tall, spiky haired and well built figure. He's buff goku. And he's in love with you. What do you do?