Just started my second play through (on difficult setting as oposed to normal)...
POSSIBLE SPOILER FOR THOSE WHO HAVEN'T GOTTEN 1/4 OR SO THROUGH PERAGUS MINING STATION
When I take control of T3 for the first time on Peragus, where he must use a Deadly Sonic mine on the sealed door that contains computer spikes.....well, on the Difficult setting it says his skill is too low to place it.
Thus, you are effectively stuck.
The only solution is lowering the difficulty to normal, blowing open the door via the mine (skill no longer too low), and then upping it back to difficult.
No big deal, but a flaw that should be fixed I think.
No other way of going about it....and I dun see how they didn't catch this in beta. Ah wait....there was no beta =)