One way to reign that stuff in, for instance the telekinetic super assassin/saboteur, is to require the telekinetic to 'see' what he is manipulating.
So he can't just create heart attacks or shred starship parts automatically, and LE can tell when most telekinetics are trying to internally harm murder victims, as telltale as a bullet.
Pushing the powered down air/raft over the cliff or telekinetically tossing a crowbar into the MHD turbine should be eminently doable assuming the psi is in LOS. Seeing inside the body, not happening.
For those who want a middle ground of such things being possible but not widespread, there is the option of requiring both the talent to 'see' and the ability to affect.
For fine bodily surgery/assassination, I would require the combination of Telekinesis and Awareness.
For undetectable sabotage I would require Telekinesis and Clairvoyance- even in LOS of the device to be sabotaged, as the telekinetic has to be able to 'see' into the machine to do damage effectively.
For memory wiping, has to be both Telekinesis and Telepathy (so the right brain cells with the memory can be identified and purged without turning the subject into a vegetable- which would have implications for hardcore Zhodani 'reprogramming' techniques and limited personnel).
The advantage of this approach is that the OP's horror show can happen, but it will be relatively rare to have the 'right' combination of abilities, and more rare to have more then one set possible.
That, and the need to use BOTH talents is very draining and will likely mean the psionic will have to be very close- limited range.