How can I use get_the_excerpt outside the loop?

I'm using a plugin to query and display a CPT on a page. The plugin outputs the post thumbnail, title and a shortened version of the content (using wp_trim_words). The developer tells me they don't use the proper excerpt because this can't be done outside the loop.

Using wp_trim_words makes the output look like a bit of a mess. It would look nicer and be easier for my client if it would just work with get_the_excerpt.

Do you have any suggestions of how I could get the excerpt to work outside the loop, or is this an impossibility?