The following dialogue is from Final Fantasy XII:
さて……王宮に忍びこむ方法じゃがな。
まず5番倉庫に行ってみい。
あそこに扉が2つあるじゃろう?
I bolded 行ってみい
. I'm not sure what this is, and there's no dictionary entry for みい
. My guess is that it's a dialect form of 行ってみよ
with the last vowel dropped. I think that without the /o/ at the end, /miy/ becomes /miː/. Does this make any sense?
Here's a picture from the game: