the video you have posted shows a sub diving, firing at a BB, crit diving for DC's then re-surfacing to fire again. at no time does the sub fire when in crit dive.
you think that the sub is in qrit dive because you can not see it due to lack of sonar on nearby ships. when the DD comes close to sub and drops DC's you can see the sub, you can see it submerged, crit diving then coming back to submerged state.
at NO point does the sub fire torps when in crit dive.