Behave wildly, iron into track (3,4)

I believe the answer is:

run riot

'behave wildly' is the definition.

I can't explain the rest of the clue.

(Other definitions for run riot that I've seen before include "Raise hell" , "Grow profusely (of plants)" , "high-scoring test match" , "Act wantonly, without restraint" , "Lose control" .)

I've seen this clue in The Times.

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