SOLVED. Adult Thriller read in 2017-18. Veteran goes to a private university that comes under attack and he fights back.

[Maximilian]

I read a book back in 2017-18 that I picked up from a resale bookshop then must’ve donated it. I have a vague memory of it being centered around a main character who was a veteran attending a university, I believe it was a private school. Then the school comes under attack, possibly terrorists or mercenaries, and the main character defenses himself and the school/classmates.
Any help is appreciated!

[Kris]

Trigger Warning by William W. Johnstone?

Google Books preview:

- https://www.google.com/books/edition/...
- There are different cover images.

Google search of Goodreads:
site:goodreads.com "thriller" "veteran" "college" "attacked"

[Maximilian]

Yes! Thank you!

[Kris]

Great! Glad you found your book, Maximilian.