No, I would not expect "in tandem" to be used that way. What do you want to say exactly? In pairs? In line? All together?
Oh, and by the way, you have a typo in your sentence. The omission of the word "of" made me think that entire class was to be outed -- which could be understood as meaning that the entire class is secretly gay, but that fact is now going to be ann
The word "of" seems to be optional when you are referring to a door or or window.
You'll also hear things such as "There is a paper is sticking out (of) the bottom/top/side/front/back of the box" ("of" is optional), but NOT "There is a paper sticking out the box" (i.e. in this case you must use "of").