The phrasing of the Possibility Shield Psychic Power in my opinion leaves room for interpretation. "... the psyker and a number of allies equal to his PR within range of the psyker gain a +10 bonus to one roll each Round."
There's no mention of the type of roll this can applied to. For instance if the player decides to use a fate point to heal d10 wounds they can boost this roll to d10+10 which is a huge difference.
Is this how this was intended?
Compared to Vortex of Doom which considering the XP cost should be a much stronger power this seems out of balance. A challenging (+0) Agility Test doesn't seem to be a threat to either a Space Marine nor to any of their enemies.
My last question is about the Force Weapons possible extra damage if they are wielded by psykers. "...he may ... channel psychic force and killing will into the blade...". Does this mean that enemies which are immune to psychic powers are immune to this extra damage as well?