It certainly appears that the couple fought the current to get back to
the boat instead of simply drifting with the flow and slowly swimming
to the surface to abort the dive.  Too bad.

Last August in Fiji, I tried to help another diver in a (too strong
for him) current.  When it became obvious that the current was too
much for me to pull both of us, I stopped, the other fellow gave me
the up sign and drifted to the surface to await a pickup, and I stayed
below to finish my dive.  Had he just held on after I stopped, I would
have given the up sign and both of would have drifted to the surface.