What do you mean by "outsider"? That's a bit silly! NIT Hamirpur is a national institute managed by the central government for all Indian citizens. If you're staying in the hostel, you have the option to transfer your voter ID and vote in that area if you wish.
The situation you're thinking of was more like what happened at NIT Srinagar before Article 370 was revoked. You might have seen the news about the Indian flag issues there. But remember, a firm approach can handle that "outsider" mindset effectively. In NIT Srinagar, the presence of the Indian Army and CRPF helped deal with such problems, and things are stable now.
These "outsider" issues mainly arise when: