The “tsunami” approaching Saudi to which Bhadrakumar refers, of the Shia variety, threatens the Kingdom by rousing it Shia subjects, many of who inhabit the oil-producing Eastern provinces. Than there is the radical Sunni tsunami, represented by ISIS, Nusra, etc. that threatens the Kingdom’s legitimacy from within.
The Saudis’ restraint in the face of the region’s turmoil has been dictated by knowledge of their inherent weakness. Military involvement is a big gamble.