Officers alone should not be able to shoot if there are only officers in the squad...
It was almost comical when my friend had an 2 squads with only officers left that were flame throwers and had Merciless assault... EACH GOT 5 DICE ON A HEX WITH ITS COVER TAKEN OFF!
Very useful bit of info from the RCD (Rules Clarification Document) which can be found on BGG:
Q: In Tide of Iron, does each figure represent one soldier?
A: No. Each squad (one base with up to four figures) is a representation of somewhere between 10 to 24 soldiers – it varies a little from scenario to scenario. The easiest way to look at this is to think of each base as a small group of soldiers (about 12 maybe) and the figures – and specialty tokens – represent what type of squad it is and its threshold level (2 to 4 hits) before being removed from play.