I play Magic: The Gathering and I just had a really strange game with my opponent. We were both about to die (both sides with 2 life) when we both set down instants that damaged each other (at the same time). I played the red instant Shock, and she played the red instant Staggershock. It was my turn. It was kind of an awkward coincidence, so we called a draw. Is that logic correct?
No, it's not correct, and no, it wasn't a draw.
As you know, if they were killed at the same time, it would be a draw. But they weren't killed at the same time. MTG is a turn-based game. It's impossible to cast two instants at the same time (at least under normal circumstances), and it's completely impossible for two instants to resolve at the same time.
Whoever had priority got to cast their instant. Their opponent then got a chance to cast an instant in response. The instant cast in response, being cast last, will resolve first.
The game would have ended before the first instant had a chance to resolve.
- It's not possible to determine who had priority from the info you provided. Being your turn, chances are it was you unless you just finished casting a spell.
The game shouldn't be called a draw, because you weren't killed at the same time.
Magic: the Gathering uses a system of priority and a thing called stack. You can only cast spells and activate abilities when you have the priority. After you cast a spell (or activate an ability), but before it resolves, your opponent gains priority and has a chance to response to whatever you cast, by casting his own spell (or activating an ability) which will put on stack on top of your spell.
The situation in your game looked like this:
Stack is empty, it is your turn, you have the priority, both you and your opponent have 2 life.
You cast Shock and pass priority
Your opponent gains priority and responds to your Shock with his or her Staggershock
Stack looks like this
You start resolving spells from the top, so the first spell to resolve is Staggershock. It resolves and deals you 2 damage. Before moving on to resolving Shock, state based actions are checked, you have 0 points of life, you lose the game as a state based action.