All of you, stationed in your assigned positions in the various formations, protect Bhīṣma alone, all of you completely

Duryodhana reveals his true concern: the protection of Bhīṣma is strategic, not affective. The elderly patriarch is the pillar of Kaurava strength, and Duryodhana knows it. Without Bhīṣma, everything collapses.

The instruction yathā-bhāgam (according to the assigned portion) indicates a rigid military disposition. Each warrior has their precise place in the vyūha. The eva (alone, only) emphasizes absolute priority: all other objectives secondary, protecting Bhīṣma is paramount.

The ending sarva eva hi (all, completely, in truth) sounds almost desperate, as if repeating to convince himself.