PDQ
against the clock
amain
apace
at flank speed
at once
by forced marches
cursorily
decisively
directly
double-quick
expeditiously
fast
feverishly
flat-out
forthwith
full tilt
furiously
hand over fist
hand over hand
hastily
hell for leather
hell-bent
hell-bent for election
helter-skelter
hotfoot
hurriedly
hurry-scurry
immediately
in double time
in double-quick time
in high
in high gear
in no time
in passing
in seven-league boots
instanter
instantly
lickety-cut
lickety-split
on the double
on the instant
on the run
on the spot
pell-mell
post
posthaste
pretty damned quick
promptly
pronto
greedily