To be honest I don't think panic matters so much with the N method. It is fast acting. It's probably not going to make a large difference to the mechanism. It would be nicer for you if you chilled out those last few mins but the truth is you're never going to be totally relaxed if you're an anxious type. So at least it's quick and reliable and pain free.
Also, even if Mexico is dangerous, it's probably not so dangerous it would perturb you from getting N if you knew you could procure it, right? Feels to me that the risk of being randomly targeted as a tourist is low for the reward of the best available method. Not like you're stepping into Sudan. Depends how bad you want it really. Truth is getting N is never going to be extremely comfortable these days, you have to go to a country with little to no oversight and put yourself out there.