Why does Satan choose Eastern Standard Time 12:00 AM to end the world?

I agree with the out of universe answer that EST was chosen because it's an American film, however, I think there's a better answer to be found in-universe:

• Satan needs to perform his ritual at "midnight."
• It's always "midnight" somewhere, if we consider time globally.
• The events of this film take place in New York City, which is in the Eastern Standard Timezone.

Logically, Satan needed to perform his ritual at midnight, Jan 1 2000 local time, wherever he happened to be when that time came. As it happens, he was in New York, which means EST, so that's the midnight he needed to use.

As Ankit mentioned in the comments, it's probably just to avoid confusion.

But then again they could have used IST (i.e. time in Israel) and explain it in one short scene and two or three sentences.

However, there are more problems with this, not just a potentially confused audience:

The Israel Standard Time (IST) is at UTC+2, so the difference to the US would be 8 hours (UTC-6 to UTC+2). This would put the whole end of the world into broad daylight at around 4 pm, if it still plays in New York (why not Megiddo to bgin with?)? Lots of people around, everything bright, less dramatic candle light, etc.

And why the name Christina? That's probably just the authors, considering it's the female form of Christian, which would be an even more blatant choice – at least for an English speaking audience – I would have called her Josepha or Jessie.