From Sixth Guru ji's times, there were lot of saint soldiers, which became a more known concept by the tenth Guru ji's times. Most of the sikh leaders after tenth Guru ji, who were leading armies, were also inclined spiritually so much, a few examples like Banda Singh Bahadur, Hari Singh Nalwa, Maharaja Ranjeet Singh, Baba Deep Singh ji... the list continues. Then there comes the freedom fighters who belonged to Punjab, I sense their contribution towards poems and writings so much, and spiritual inclination seem to be giving so much direction to their works and acts. Gurudwara Hemkunt Sahib ji was located by defence personnel, and he also did lot of seva in terms of engaging in coversation with with local people, building gurudwara, paving out way up there. And now recently we came to know abt Gurudwara Pather Sahib ji. I just picked up a few handful incidents to support the claim, just to give u a hint. That gave me a hidden connection of defence services guys more inclined towards spiritual ways than other professions. May be because they are more disciplined and get more time to contemplate during their guarding times!