Halliday & Matthiessen (1999: 221):
Coming back now to the distinction between type (1) circumstances, those realised by adverbial groups, and type (2), those realised by prepositional phrases: as typically happens in language (since grammar abhors determinacy), we find a crossing between the two types.
This happens mainly in one direction: there are prepositional phrases which construe qualities of figures, and hence function as circumstances of Manner; for example in a hurry, without proper care (cf. hurriedly, carelessly). Typically these may also appear as qualities of participants, as in he was in a hurry (realised as Attribute in a clause), a man in a hurry (Qualifier in a nominal group — not Epithet, since English does not like phrases and clauses before the Thing). These usually involve some kind of metaphor, either (as here) grammatical metaphor, where a quality or process is made to look like a participant, or lexical metaphor (metaphor in its traditional sense) as in they left the matter up in the air.
Less commonly, we find a cross-over in the other direction; an example would be the adverb microscopically where this has the sense of 'using a microscope' (we examined the tissue microscopically).