Interesting dilemma. Practically speaking, obviously I wouldn't start smoking, because of the health risks, but a nicotine-free vaping pen could be used without inhaling, even without doing anything more than just putting the mouthpiece to the lips, so if that looked like it would do the trick without any significant risk of being found out, that might be the way to go.
A lot would depend on whether or not there was a danger of inhaling the slipstream from other people's cigarettes. The occasional mild whiff of tobacco smoke (for example in the open air) probably wouldn't do any harm unless the person were hypersensitive to such things, but I'd be wary of anything much more than that. I wouldn't have believed this "secondary health risks" thing about tobacco smoke at one time, as it's hard to see how the relatively small amounts of toxins inhaled by a secondary smoker could be anything like as risky as the amounts an actual smoker is exposed to, and even regular smokers only have (something like) a 50:50 chance of getting a serious smoking-related illness, but I gather the available data says otherwise, so I guess the relationship between dose and health risk isn't a simple linear one, though it still seems counter-intuitive to me, as the lung cancer risk does appear to be linearly related to the number of cigarettes smoked. All things considered, best to play it safe, maybe one day it'll come out that the health authorities in their zeal to stamp out smoking weren't telling us the truth, or there was a mistake in their research methods, or maybe we'll find out why they were right. Secondary health risks from vaping are thought to be negligible, at least so far, though that's not an issue here.
Then there's the moral question. I don't like deceit, but when an authority acts like a jerk and imposes unfair rules like this one, my view is that they forfeit the right to our honesty, and all we need to remember is the 11th commandment - don't get caught. It's kind of weird because usually I find myself defending smokers who get horribly demonised by health fascists, but in this case they're getting preferential treatment and I don't see how that can be justified.