Ally Cat of the canals

"to go West you must go East" you know. Could this not refer to Dany having to use Vic's ships because he is from the east? Also why can't Dany defeat the Khal with her dragon and show up to Meeren with an army of dothraki screamers, they only follow the strong which she would be. That why she would also be going back to go forwards as she is returning to the Dothraki

I thought the horn killed the person who blew on it so if Vic tries will it kill him and burn his insides up? Does the horn need someone with dragon blood like Dany or Ben Brown Plumm to blow it?