1998 Jeep Grand Cherokee Laredo: Starting Issue

My 1998 Jeep Grand Cherokee Laredo wont start, and I think it's a possible security feature flaw.

I've had this same/similar issue before:

I start my car, only to have it turn over, start, and then immediately shut off. The only way to get it to stay on is to hit the gas at the precise second the car starts and keep it held down in park just to keep the engine running. Letting go of the gas causes the car to shut off immediately as before, though. Through doing this for about 10-minute stints, I have heated the engine block (it's -15C outside), and confirmed that my battery is working fine.

The first time this happened I was informed that it's a security feature, and all I had to do is turn the key in the locks on the driver, trunk, and passenger doors 5+ times so the car recognized the key again, and it would start up just fine.

This has now happened three times, and all three times that remedy worked immediately and without issue. Today, however, the same thing happened again, except when I turned my key in the locks it still would not start. I went on to try this remedy with three alternate keys, four in total, with no success. The only difference between this time and the other times this has happened, is that it is now the middle of winter, and daytime temperature is roughly -15C, dropping to roughly -25C at night -- and I live in Edmonton, Alberta, so it's only going to get worse.

I am currently at a loss, as any attempt to heat the car only heats the inside of the car and the engine block, and not the door lock sensors, which I fear are frozen over and are the root of the problem. I'm hoping there's a way to disable this security feature altogether, so I no longer have to deal with it; although any solution would be a welcome one, at this point. Any help, input, or advice would be greatly appreciated.