Daf Yomi - Yoma 69 - Careful as he Sleeps

The Sages created an injunction that one should not lie down on clothing that has shatnez in it for perhaps some of the threads will wrap around his skin. According to this, the Gemora questions the permissibility of the kohanim resting on their clothing (according to the opinion that there was shatnez in the belt).

The Maharatz Chayus brings a proof to the opinion of the Maharsha who holds that the concept of אין שבות במקדש - "there are no injunctions in the Mikdash" only applies by laws pertaining to Shabbos, however other halachos would be applicable even in the Mikdash. However, he rebuts this proof by explaining the reason behind the concept of אין שבות במקדש. This is because the kohanim are meticulous and extremely careful and therefore there is no justifiable cause for the injunction. However, here we are concerned of what might happen when the kohanim are asleep and therefore the logic does not apply.