[Hillarys Gate Cult]

I read that he turned down OCS. No idea why, the articles don't say. I can only guess that it would have possibly took him away from the Rangers.

[Lakeside]

Yes, it's easier to get into special forces as an enlisted person rather than as an officer. Officers usually come up through the ranks within the special forces.

[Jimmy Valentine's brother]

OCS would have kept Tilman out of the fight for a longer time due to added training. I believe he wanted to get into the fight as quickly as possible. Ranger qualification was the fastest route to the tip of the spear.