면서 들어가다

walk in while doing X

The while form attaches your state or your words as you go in, and most of these lines quote the thought you had walking through the door: going in shaking with nerves, going in thinking so this is the Sony building, going in announcing that you have bought Twitter, going in wearing dark sunglasses. It is a natural way to set a scene, since the mood on entry is what the story turns on.

Register: casual storytelling