Green’s Dictionary of Slang

flash v.4

[SE phr. quick as a flash]

(UK black) to rush, to run away; also used trans. (see cite 1946).

[Aus]Clipper (Hobart, Tas.) 25 July 4/6: Get the city down and hold it, / Flashin round jest as they pleese, / That there game ain’t in the running / Nor by any means the cheese.
[US]D. Burley N.Y. Amsterdam News 18 May 19: [She was] flashed off to a ‘hot’ flat where she was given the works.
[US]R. Prather Scrambled Yeggs 117: Flash down there right now, give the boys at headquarters the whole works.
[Aus]J. Hibberd White with Wire Wheels (1973) 216: I’ll flash over and see it.
[US]L. Heinemann Paco’s Story (1987) 16: The senior class’s butter-headed peckerwood flashing around the locker room.
[UK]C. Newland Scholar 217: Right now, I gotta flash man. I’m gonna go and see Sonnie.

In phrases

flash it (v.)

(UK Und.) to run away, also as imper.

[UK]Oxford Univ. & City Herald 1 Sept. 4/2: Mr. R. continued to call out ‘murder’ so loudly, that the whole neighbourhood were alarmed, when he heard a voice say, ‘flash it,’ (the slang phrase to be off).
flash off (v.)

(W.I./Rasta) to push away.

[WI]M. Montague Dread Culture 131: Di Bwoy jook mi dung wid him .32 and hold on pon mi hand. Mi jus flash him off and pull out mi .45.