There were thousands of thoughts spinning round Leomum's head,
when, together with her son, she was going under the deck of a submarine.
"What is the saturation of CCHS kids under the water?
If they don't breathe well high in the mountains, maybe under the water they don't breathe at all?
Has someone ever checked that?
Has someone with CCHS travelled on a submarine before?"

Now Leomum knowns.
If something was a to happen to Leo at 30 meters below sea level, it was rather hyperventilation ;-)
For the whole 40 minutes of the trip, Leo's saturation was 100.
He was so excited, that he breathed even better than usual.

Additionally, it appeared that Locomotive (Leodog) can speak english.

And these are the views that the Leodog observed: