Being run out for a single means disaster (4)
I believe the answer is:
ruin
'a single means disaster' is the definition.
'ruin' can be an answer for 'disaster' (I've seen this in another clue). I am unsure of the 'a single means' bit.
'being run out' is the wordplay.
'being' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'out' indicates putting letters inside.
'i' put into 'run' is 'RUIN'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for ruin that I've seen before include "State of devastation and destruction" , "Destruction or bankruptcy" , "Wrecked building" , "Wreck" , "fall" .)