It was in this video. It is at around 2 minute and 34 second. Here is the context:
I was in a small valley called the Korengal Valley in eastern Afganistan. It was 6 miles long. There were 150 men of (a/the) battle company in that valley.
Dictionaries say, in this context, that company is a military unit of soldiers and it is a countable noun. Then why did the speaker decide to leave any article out?