Way to show up for the party. Now he can get off the roof. More than likely, the roof access is locked on both sides of the door. Building management do not want people coming into the building that way and do not want people wandering around up on the roof, due to the liability issues. In the event of an emergency, go down the stairs, not up; most fire departments do not have the means to extricate people from the roof of a high-rise building.
The way I'm reading Clarke there is no -way- that he would ever do that to Femme... (at least, not intentionally... And if he did, he would apologize profusely.)
Likely true - but not everyone knows that and those that know Femme best are probably well aware of where here weakness are. They'll err on the side of protection of their friend rather than trust for a stranger. At least until they get to know him.
I wonder how Cyannas friends will take to the news that Clark got to hear this much of her story on the first date - that she is already... comfortable being vulnerable around him. Will they see it as a positive sign, like I and I think Cyanna do? Or will they be more concerned with the dangers than happy about the possibilities?