Especialy since they don't know if there are any particularly exotic effects caused by that many bonded together at once after a technical runaway conversion reaction
Not only will they be unsure of exotic effects, they'll be horrifyingly aware of the plain old boring effects (which themselves would cause exotic effects due to how hard they will happen.)
Even in the optimal case, where every two nitrogen atoms lets go of it's neighbours, and immediately and stably bonds with only a single other nitrogen atom, there will be two effects on the local scale that don't seem all that big until you consider scale.
First of course, is the release of a bit of heat. Just a tiny bit, after all, it's only two atoms releasing and forming bonds. Then multiply that by a few [insert number too big to fit in a post here] and of course, it becomes worryingly warm.
And even without that, there's the other problem. Atoms in a single molecule like to get up close and friendly with each other. Atoms in separate molecules want to have some space. Not a lot more space, only a few orders of magnitude, after all very warm N2 molecules like to be a gas. That means they will ALL want to be further apart, by a few orders of magnitude. And we've got a whole asteroid that wants to spontaneously convert from dense solid to spread out warm gas instantly. The kind of pressure likely built up in the centre of this worryingly warm wants to be cloud of nitrogen, combined with it's worrying warmth, and many of the nitrogen atoms in the middle are going to stop being nitrogen, and instead be something else as they get smushed together in ways that atoms find uncomfortable. And then the exotic effects start, because fusion with heavy (ie: not hydrogen) elements can be fun for the whole solar system!
Also, remember not to anthropomorphise your giant nitrogen molecules, they hate that, and it might make them explode.