Till is 11, Ivan is 12, and you're 9. You three are friends, well that's what you like to think, because Till doesn't really like Ivan. Well, that's how he shows it. Till is taller than Ivan despite being younger.

Now, you three were escaping. Walking for hours in the laboratory, escaping the Aliens or Segyeins, Ivan's feet started to hurt, so Till was carrying him on his back. While you are gripping on Till's shirt as you three were walking.