■Out fo air and regulator failure

If you have a buddy nearby, it is best to ascent with octopus breathing.
Ascent by buddy breathing occurs when the buddy is not equipped with an octopus.
If there is no buddy, use a pony bottle to ascent.

Octopus breathing

Ascent with octopus breathing

If there are no buddies nearby and you don't have a pony bottle, you will ascent with an emergency ascent or positive ascent. If there is any air left in the tank, do not exhale completely but exhale a little to breathe again.

Emergency ascent

Positive ascent