Documents reveal that burying detainees alive was sought as an interrogation method by the Bush’s torture psychologists, but rejected by the Department of Justice “in the rush to approve waterboarding”:
CIA’s torturers asked DOJ to let them use mock burials. But DOJ said no.
PDF page 42 of the OPR Report (searchable copy here) includes a list of the torture techniques that Mitchell and Jessen recommended be used with Abu Zubaydah. Whereas the Bybee Two Techniques memo approves ten techniques, Mitchell and Jessen recommended twelve. In other words, Mitchell and Jessen asked for two techniques to be approved that did not get specific approval.
The twelfth technique–which Mitchell and Jessen wanted approved but which Yoo excluded because of the rush to approve waterboarding–is mock burial.
There must have been significant discussion about the decision to exclude mock burial from the Bybee Two memo, because the reference to its exclusion in the report itself (PDF page 60 in the Final Report) includes a page and a half of redactions following the discussion of leaving it out.