I went out quietly and came back quietly to continue my study.

In fact, your main problem is that you are afraid of being occupied by others when you go out.

For such a problem

I suggest you

1, if you want to continue studying here, you can put your books on the table first. I believe that a person with quality will understand that there are people here as soon as he sees where there are books.

If you want to come back when you go out, but you have something on the way, you'd better come back and take the book away for others to learn.

If you return it later, you can show it to your classmates first. If someone comes to tell you that someone has been here.

If you go out and don't come back at all, then pack up and leave, without delaying yourself or others.

The above is the general practice.