I don't think anyone is suggesting that a terrorist using automatic weapons on the public or police they should not be stopped as quickly as possible and if it costs the terrorist's life very few tears will be shed.
A shoot to kill policy is different, it is a preference for dead bodies over arrests and trials and this should never be the policy in civilised countries.
I would describe my view as being that the policy should be shoot to protect and to save lives. Where shots are taken there are likely to be deaths but they are not the aim or the policy.
History
For those too young (or insufficiently British/Irish) to be aware there was considerable controversy about whether a shoot to kill policy was in operation particularly with the SAS with regard to the IRA and was particularly controversial when the [3 IRA members were shot dead in Gibraltar](http://www.bbc.co.uk/history/events/three_ira_members_shot_dead_in_gibraltar).