Captain Ian Macalwain is a Captain within Red Troop during Series 2. His background combined his personality meant that he never really settled in to the troop well. He bypassed a black bag op and was found to be having an affair with Pete Twamley's wife which resulted in his eventual death.
He is killed in Episode 6 of Series 2 once it is confirmed that he is having an affair with Pete Twamley's wife. Henno who finds this out shoots a burst of shots into him using an enemy's weapon and then claims he was shot by the enemy. He is then placed in a freezer nearby by Henno and despite being the ranking officer no reprecussions come of this either directly after or at any other time after the event.