First of all: I do not hate Psykers
Okay, you need to get a psyker into trouble. REAL trouble. Unfortunately, you are a bit …generic…about the situation. So, it is a blank canvas and you need a Biomant-Telekine-to be put down. Generally, a Rank 8 character of this class is a little trouble..
Corruption was already mentioned. Your Psyker might already have some of it. Remember, any roll on the PERILS OF THE WARP although causes a CP as well…. How much are already their? Could a holy zealot become an enemy of him?
Your pc are high class, so will be some their enemies. Giving the “bosses” Psy-Jammer-Amulets (IH; p. 191) will at least help against indirect damages. Torpor (IH p.194) is a nice idea as well. Toxic Syphon cannot be used on oneself BEFORE the poison starts working. It is NOT a reaction. But I think it will not be deliverable by food or drink. Is said Psyker able to catch projectiles? Needle Weapons could deliver the poison…if there would not be all of this armour… but a sniper could deal with this.
Besides high-Quality stuff, mundane means are useable as well. Some people will not face a psyker to fight fair. They might rather sneak around to know where their enemies are living and where they regularly go and will plant a bomb. Of course, this will only work if you start your adventure with an attack on the Acolthey (or some roles to make them notice that somebody sneaks around) or if you have an adventure where they need stay in one place for quiet some time. Other option for a bombing run is to lure them into a trap. An anonymous call telling them “I have got information for you, meet in the Jollester Hostel, Room 45, in 2 hours”. There is a small pict capturing device, signalling to Room 27. Where three guys sit and watch a pict device…in their hand the initiator for the bomb under the bed. Place a puppet on the bed, face down. Blow up the whole room with 2kg of Fyceline (2d10+10 Explosive Damage; 10m Blast; see IH p. 178). Allow for a difficult Awareness test to notice camera. If this will keep them from entering…fine…otherwise… KA-BOOM. But keep in mind that this is heartless and not very sportsman like
(To be continued)