Elimination reaction with 1,2-dibromo-4-methylcyclohexane I was doing a question from a practice exercise on the topic of elimination reactions and alkene synthesis. It is shown below:



I predicted that the product would be 1,2-diiodo-4-methylcyclohexane because I thought the reaction conditions favoured substition with iodide via the $\ce {S_N2}$ mechanism. Firstly, iodide is a rather good nucleophile and secondly, the substrate is a secondary alkyl halide. Even if it was not $\ce {S_N2}$, I would expect perhaps $\ce {S_N1}$ since iodide is a rather weak base and the conditions do not seem to favour elimination. However, the answer provided is very interestingly, 4-methylcyclohexene. Would someone kindly enlighten me on where I went wrong?
Dehalogenation of vicinal dihalides by iodide ion occurs stereospecifically and
  concertedly via an $\mathrm{E2}$ mechanism. An anti-coplanar arrangement of both bromine atoms is required (see diagram below):




Since, the given compound is a 1,2-trans-dibromocyclohexane, two bromo groups  can arrange in 1,2-anti-diaxial positions in one of chair confirmations, fulfilling the requirement. It won't be possible if it'd have been a 1,2-cis-dibromocyclohexane.

Reference: Structure &amp; Synthesis of Alkenes (Chapter 7): Leroy G. Wade, Organic Chemistry; 8th Edn, Pearson Education Limited: Harlow, Essex, UK, 2014.