Here's the thing. The Psyker always goes first, and if the Psyker goes first, the Vindicare loses, no question. Don't believe me? Consider Preternatural Awareness (which can also be immediately dismissed after it grants him the crucial first turn), and think of all that easily achievable Overbleed.
Also, let's say the Vindicare does Sprint; Force Barrage as a singular example has a range of up to 240 meters, also, assuming WP 80, Psy 10, Telekinetic Discipline Mastery, Power Well 2, Discipline Focus (Telekinesis), Unnatural Willpower 3x. Let's see what this works out to:
Threshold: 16 vs 5.5 * 10 (Psy Rating) + 4 (Power Well 2 & Discipline Focus) + 8 * 3 (WP Bonus 8 & Unnatural Willpower 3x) = 83
So on average, this gives us 13 increments of Overbleed 5, in addition to the base effect. This translates into (24 + 13)*(5.5 + 24) * .8 = 873.2 Damage on average, consisting of 29.6 bolts on average, each bolt dealing 29.5 damage on average. In the immortal words of Trinity: "Dodge this."
Also, let's not forget that a Psyker can sustain multiple powers simultaneously for just such a contingency as a Vindicare; maintaining Barrier, Flameshroud and Preternatural Awareness is very doable for a top level Primaris Psyker, and can be dismissed as needed (as mentioned, Preternatural Awareness is basically disposable). This combination allows the Psyker to always go first, renders him immune to Fire/heat and impact/physical based damage, and 75-50% resistant to just about everything else. Coupled with the dodge/armour/toughness typically available at this level of power, and he is about guaranteed to survive any first strike capability.


Apologies if I seemed off topic.