I don't think a lack of courage was a problem.
I think if you are in the FBI, you do things the FBI's way or you turn in your badge.
I think they acted with great courage, to attempt to face down guys with an assault rifles armed with 5 shot Detective Specials as their main weapons.
I personally wouldn't expect to walk away from that scenario...
Life has taught me not to be so arrogant...unless, maybe, I was feeling really lucky that day...but no, not even then.
TC