A Scottish idiom that strikes English ears as strange is to sleep in. This simply means to oversleep. To sleep in one’s shoes is to die a violent death as many did in George Muir’s The Clydeside Minstrelsy (1816): The dreary eighteenth day of June Made mony a ane sleep in their shoon; The British blood was split like dew Upon the field of Waterloo.
Sleepin deid, or nearly dead through lack of sleep used to be a common state for general practitioners in a one-man practice, as George Abel records in Wylins fae my Wallet (1916): The doctor wisna sweer to road [reluctant to start travelling], Tho’ sleepin’ deid wi’ fag [tiredness].