I did that :D and I almost died
so don't
or try not to
Like the person above said the desire in part comes from wanting to spare others the pain, or cos you are too tired to keep up appearances, or cos you want to wallow in misery alone, cut off from those walking-talking reminders of reality. In general there might not be a concrete reason its just a strategy of that part of your brain that wants to destroy you to end to protect you from the pain, it's a step closer to that and you both know it. It's like giving in to that general urge with small easier steps. That one being a particurarly alluring one.
but if you can, don't
keep fighting
An incredibly dumb way to fight it is to just... give up rationalizing it really. Don't look for excuses or reasons or anything just when the thought comes shuhs it. Cap its ass mentally as soon as it steps a foot in your brain. I did that too with the suicidal ones. Don't even let your brain finish the sentence. It's supressing, sure, but it works sometimes and it allows for less of that and an easier fight.
If you rationalize something, let it be the positive aspects of socialising only. The things you like to do with friends or gals or gals or gals or gals i know you like gals or people in general. Focus on that. Important to accept you wont always be able to so and that these awful thoughts will creep in, it's mostly about having the tools to deal with them the most ammount of times.
there are good things going on in your life, sucks you have to deal with this shit in your head while it. Keep up that fight and take it as easy as you can whenever posible <3