Security capitalization

I'm editing a short story (for context, the author is English, living permanently in Australia, and aiming for publication in the USA). In one scene the main character says something like: "We couldn't stay here: security would throw us out." Would the word "security", as a department, in this case be capitalized here as "Security"?

Solution 1:

In general the rule is that capitalize a word if it is a name. If the group that does the throwing has the name "Security" then capitalize.

Here it seems likely the people speaking don't know the formal name of the group, so it is not possible to make a definite decision. But capitalizing has the advantage that there is no possible confusion with other meanings of the noun "security".