τὸ δ' ἐξαίφνης τὸ ἐν ἀναισθήτῳ χρόνῳ διὰ μικρότητα ἐκστάν → suddenly refers to what has departed from its former condition in a time imperceptible because of its smallness
τολμηρόν: τό1 дерзание, смелость Thuc.;2 смелый поступок, подвиг Arst.