Crossword Genius

As reactions get wild, taking time out to leave (7)

Ross

I believe the answer is:

arsenic

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'as' is the definition.
(synonyms)

I don't understand how the remainder of the clue works.

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(Other definitions for arsenic that I've seen before include "Famous stage comedy ''. . . . . . . and Old Lace''" , "Toxic metalloid element" , "-- and Old Lace (play)" , "Brittle grey-green semi-metal, atomic number 33" , "Powerful poison" .)

I've seen this clue in The Hindu.
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