Runs off to secure ten contracts (6)
I believe the answer is:
flexes
'contracts' is the definition.
'runs off to secure ten' is the wordplay.
'runs off' becomes 'flees' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to secure' indicates putting letters inside.
'ten' becomes 'x' ('X' can be a synonym of 'ten').
'flees' going around 'x' is 'FLEXES'.
Can you help me to learn more?
(Other definitions for flexes that I've seen before include "Bends joint or muscles" , "Moves or bends muscles" .)