The sentence is taken from a manga in which the character kills people at a TV station in order to threaten the world :
Hello (ladies and gentlemen of the) world... for only a very short time...
The first thing I'm not sure about is if テレビに is the agent of もらう and something like お前たちを is implicit: I received the favor from the television to let me disturb you.
The second is the combination of させてもらう and 事にする which to my understanding means "decide to" : is it a way of being ironic? like I decided the TV would kindly let me (kill them and) disturb you guys.
Thanks for your help.