Seems very strange to try and abduct a serviceman in an area likely to have (armed) patrols with the Security state being 'Severe' isn't it?
https://www.mi5.gov.uk/threat-levels
If they were waiting for a 'random' runner rather than a serviceman/woman or a member of a service family returning home, wouldn't you do it somewhere a bit more off base?
That just makes no sense. I
think it's clear that they were out to get a serviceman rather than "a random runner", and I would suggest that the best place to find a serviceman is at a military base, no?