Usually, when the term "patur" is used in Maseches Shabbos, one is exempt but it is still rabbinically prohibited. However, this rule is only when there is some form of action involved.

When two people perform one melacha act together, like for example, one does the akira and one the hanacha, they are both exempt. This is derived from the reading of the Pasuk.

If one person placed an item on someone else's back in a reshus hayachid, and then the second person began walking out of the rehsus hayachid, the Gemara says that the second person's act of walking is considered an act of "akira" and he is therefore liable for violating Shabbos if he subsequently moved out into the street and stopped. However, this is different from the case in our mishna when an object is placed into an extended hand, where the misha rules that both parties are exempt. A hand extended into a different domain is not considered at rest bc it is not at rest on the ground of that location. But an object upon a stationary body is fully considered as if it is at least on the ground of that location.

A hand extended into another domain does not make the item held inside it to be like it is at rest in the domain of the person. This point is evident in the Mishna's rulings that if one takes something out of the extended hand from the other reshus, both parties are exempt.

If one did the wrong thing and picked something up and from one reshus and extended it into another reshus without placing down, they have violated the rabbinic law against making an akira. The Gemara wonders whether they Rabbis now penalize the person and don't allow him to bring his hand back in. Instead, he would be forced to hold his hand extended until after Shabbos. (It would be as is the Rabbis instituted that the outstretched hand is treated like a Karmelis and pulling the hand back in would be a transfer from karmeklis to a reshus hayachid) The rabbis perhaps would only say this penalty for someone who stuck there hand out deliberately.

The special procedure of removing bread stuck to oven walls is forbidden from the Rabbis on the Shabbos. If one already placed bread in the oven, and if the bread bakes, it will emerge that they have biblically violated shabbos, are they allowed to removed the bread before it bakes to save themselves? They will be violating the drabanan of removing the bread, but if they don't, they will certainly violate the biblical melacha of baking. We will learn more about this question tomorrow.