How does otacon survive at the end of Metal Gear Solid 1

Otacon survives because the colonel managed to stop the air raid from happening, and Snake requests that somebody retrives Otacon from Shadow Moses Island.

In otacons ending, Otacon is in metal gears hangar when the bombing starts, as he stands in Meryl's place when driving the car in order to escape.

The first explanation is the way the game was meant to go, I know this as in Metal Gear Solid 2, Snake has a bandana, which was given to him by Meryl, which he couldn't of got in Otacons ending because Meryl was left in the Shadow Moses Compound. At the beginning of MGS2, snake has stealth, but could of beenn given it at the beginning of the tanker mission by otacon, who he is working with.