Not very friendly....
Not really, that would be without the 请 or even the outright rude 滚开！Besides, it could be a friendly warning from the speaker.
Could be telling you to leave a damgerous situation, like a fire
it's not rude, i think it's just out of context...
Rude would be 滚蛋 (literally "roll eggs") or even 你这个傻屄，他妈的给我滚！("Get the hell out of here you stupid c*nt!")
'Please leave immediately' is not accepted
"As soon as possible" might not be "immediately", you might not be able to leave for a while still.