In the following sentence, is "Incoming!" an interjection or a noun?
Incoming! was the last thing I heard before the round went off.
I believe it's a noun and the subject of the verb "was". Am I correct or is it an interjection?
I'd punctuate it deifferently:
'Incoming!' was the last thing I heard....
The original use of the word alone was an interjection https://www.usingenglish.com/glossary/interjection.html
However, here, is not not an interjection- it is indeed the subject of the verb 'was'.