Both sides are eliminated at the same time. How can this happen? I hope to compile a complete list of abilities or combinations which lead to the game ending with no survivors.

1. Darth Vader
2. Feedback Array
3. Dead Man's Switch
4. Major Rhymer attacking with Assault Missiles at range 1
5. Assault Missiles attacking inside the firing arc at range 2 while being at range 1 outside the firing arc.
6. Captain Oicunn overlaps someone who has Anti-Pursuit Lasers.
7. Captain Oicunn with Stunned Pilot overlaps someone.
8. Captain Oicunn with Damaged Engine and Minor Hull Breach overlaps someone while performing a turn maneuver.
9. Captain Oicunn overlaps someone while performing Daredevil.
10. Two huge ships overlap. They receive one damage card each which causes them to die.
11. A huge ship overlaps a small or large ship, suffers damage and dies.
12. A ship drops Proton Bombs or Seismic Charges and moves a) a very short distance or b) not at all due to overlap. The bomb destroys all ships.
13. A ship with "Genius" drops Proton Bombs or Seismic Charges after executing a maneuver. The bomb destroys all ships.
14. A ship with Inertial Dampeners drops Proton Bombs or Seismic Charges after executing the stationary maneuver. The bomb destroys all ships.
15. Simultaneous fire: 2 ships with the same Ps shoot each other.
16. Simultaneous fire from an already dead ship kills another ship, and has to ruthlessness the only other survivor
17. Ruthlessness chaining dead man switch to kill the shooter
18. Captian Oicunn running over a rock / debris cloud and hitting someone

Yep. I've seen it come up a few times during tourneys, including once this weekend when a DeciVader killed himself to take out the opponent's ship. In terms of scoring, it's considered a Draw (1 match point) unless it's the championship match, in which case the winner is the pilot with initiative.

2 ships with ion turrets ioning each other off the board?

Yep. I've seen it come up a few times during tourneys, including once this weekend when a DeciVader killed himself to take out the opponent's ship. In terms of scoring, it's considered a Draw (1 match point) unless it's the championship match, in which case the winner is the pilot with initiative.

If you use the rulebook instead of tournament rules, the player with initiative wins.

2 ships with ion turrets ioning each other off the board?

Don't think so.

One ship moves first, leaves the board and is destroyed. The game ends without the other ship activating.

Also the rather obvious - 2 ships with the same Ps shoot each other.

Initiative wins sure, someones always gonna have init.

2 ships with ion turrets ioning each other off the board?

Don't think so.

One ship moves first, leaves the board and is destroyed. The game ends without the other ship activating.

Eh that's true too.

Simultaneous fire killing all ships

Simultaneous fire from an already dead ship kills another ship, and has to ruthlessness the only other survivor

Ruthlessness chaining dead man switch to kill the shooter

Captian Oicunn running over a rock / debris cloud and hitting someone

Also the rather obvious - 2 ships with the same Ps shoot each other.

Added as number 15.

Simultaneous fire from an already dead ship kills another ship, and has to ruthlessness the only other survivor

Ruthlessness chaining dead man switch to kill the shooter

Captian Oicunn running over a rock / debris cloud and hitting someone

Added as 16, 17 and 18.