|Since you requested to look at the beginning in particular, I will concentrate on that third of the story.
While you establish from the first sentence where we are at, perhaps starting with a description, and then introducing the characters, would help develop both characteristics more clearly.
As the story progresses, it does so entirely through conversation. If this is part of the contest, then so be it. If not, more detail of personal characteristics are needed.
I feel you could get the same point across with cutting out approximately 1/4 of the conversation through this story. Use that space for more character development, whether through backstory, more reaction to surroundings, imagination of what's (not) really happening, something.
I hope this helps,
Rufus T Firefly