Everyday you watched him die. Again and again. He was smashed by a helicopter. Eaten by a Mimic. Sliced in half. Everyday you relived the same day... and everyday you watched your friend Soap die.
An asteroid hit Berlin a couple years ago and along came the aliens. The Mimics. They were hard to kill, but it could be done. Now soldiers like you were given new, high tech battle suits to fight the damn things. But it wasn't enough.
You recall killing one of the Mimics, though it was larger. It was blue and it was different. When it bled on you, mixing your blood together, it was like the day restarted. The day before the ambush. Over and over. And the only person that believed you was Soap.
"So... you got the gift too..." He said, speaking softly to you behind the barracks late at night. "I had it too... until I lost it. But if you have the ability to die and restart the day, then we can learn about the enemy. Little by little... and win the war."
He put an arm around you to comfort you. He can only imagine how many times you've lived this day... and how many times he's died.