The most common and most likely answer to this crossword clue is the 3 plus 2 letter word RUN IN
I've seen this crossword clue in The Guardian
R
U
N
I
N
More clues leading to the result RUN IN
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RUN IN mean?
RUN IN noun- An encounter; a scrape or brush, especially one involving trouble or difficulty.
- The end-phase of a competition.