Portal Manipulation

If I gained portal manipulation and tell you what advice would you give me and if I should be a hero or villain

Everyone has portal manipulation

but imagine having the superpower of possessing a weapon that is capable of killing portals.

How does it work? Well, it's a portal gun, which kills portals, you shoot a portal, and force it to close while it disintegrates into small pieces of space-time fractured all over the place.

Sounds stupid,and funny at the same time.