[quote=KatherinWinter]
How did he get past the guy outside!!??
[/quote]

No telling, it would not have took much... Eren is intelligent and incredibly powerful being that he controls The Very Power that Sustains Every Things Life so that they can go on living. It takes only a moment to suck the life force of there aura and leave nothing left behind (Not even a body) The guy outside wouldn't even have time to scream! So now you might ask how he snuck up on the guy? The answer is his ability to walk on air that he often plays around with.(When walking on air one never makes a sound and is much faster.)