The most common and most likely answer to this crossword clue is the 3 plus 4 plus 2 plus 2 letter word THE HEAT IS ON
I've seen this crossword clue in Financial Times
T
H
E
H
E
A
T
I
S
O
N
Buddy explains!
The straight part
We know that "In high-pressure situation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in high-pressure situation = the heat is on.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.