The literary device used here is anachronism.
Explanation:
The person here is said to have been 'wobbled' on to the floor.
This is not an action that a human is often portrayed as doing anywhere so it does not really fit human description but shows a form of action that happens to things.
This suggest the situation and how bad the fall actually is.
It also suggests that the situation and the tone of the passage is rather comedic and used in a sense that is strategically that way.
Answer: The possessive pronoun in the sentence is 'theirs'.
Explanation: It shows the ownership of the idea for group skate.
Answer:
I may be able to help but what is an umbrella topic