Woman engaged in live data streaming — it could swamp her (5,4)
I believe the answer is:
tidal wave
'it could swamp her' is the definition.
The definition suggests a singular noun which matches the answer.
'woman engaged in live data streaming' is the wordplay.
'woman' becomes 'w' (abbreviation eg in Woman Police Constable).
'engaged in' is an insertion indicator.
'streaming' is an anagram indicator.
'live'+'data'='livedata'
'livedata' with letters rearranged gives 'tidalave'.
'w' placed inside 'tidalave' is 'TIDAL WAVE'.
(Other definitions for tidal wave that I've seen before include "Huge movement of public opinion" , "Very powerful movement (at sea?)" , "Large movement (of water or public opinion)" , "Tsunami" , "Huge sea surge" .)