I don't see why they would ban you from going abroad... I mean, even college kids with security clearances can go abroad (though, the program sounds like it might be one of these types; I know they are floating around in the national security field). I'll just say that if the internship/scholarship program is in the national security field (including the IC), those are extremely competitive and if that is where you want to work, you should absolutely take the internship/scholarship. You might never get another offer to work in that field as they move on to other extremely competitive candidates and budget issues become more prevalent. If I'm barking up the right tree, feel free to PM if you think it would be helpful to you.
you should talk to the company. Obviously they hired you for a reason. And if it comes with guaranteed employment, they would want you to have the best skill set possible. What does the company gain by not allowing you to travel abroad?
If there's no budging from the company, you need to figure out if the employment is really guaranteed. If it is, then you need to decide if that is definitely what you want to do for the foreseeable future. If you definitely have a job, and definitely want to work for that company, then you should make sure they will still hire you if you change your major. Employment might be contingent on you completing the program that you are currently in.
You can play with majors/minors which might still give you a lot of the same classes but let you out of some school requirements.