I find the ROF for the pistol to be quite satisfying and the knife is an excellent backup weapon. However, I must agree with the OP even if I haven't seen such a situation my self thankfully.

I usually spawn assault medic simply because there's more to do with that class than just shooting the enemy. So I'm running around dropping health kits and hitting people with the defibs and all that jazz. I also use either the stock AR or VOSS on single shot simply because its usually faster to fire off 4/5 rounds in single shot at someone's head then it is to spray 15 and wait for the 5 rounds to hit. I sometimes find myself in situations where I've just downed 4-5 people with my AR, switched to my pistol, downed the medic that ran up and the person they defibed before running out of ammo, switch to rockets, downed the other medic and the person THEY defibed, and I find myself sitting there with empty weapons and a defib kit as another medic runs up and starts to defib.

I suppose I could reload my AR and go guns a blazing on them, but that's crucial seconds where the rest of the squad is coming around the corner/over the hill with revenge on the mind. Reloading the pistol would be faster, but those rounds won't do me much go against the counter attack. Grenades are an option, but I'm cursed with the "oh shiney!" factor of some teammate somewhere ALWAYS running after my nade to get a good look at it.

So *shink* out goes my knife as I run charging into the fray! Of course by 'fray' I mean the rear and by 'charging' I mean screaming "Oh crap oh crap oh crap!". I guess its reactionary to go with the weapon you can use (even if its mostly useless for the situation) instead of taking the time to reload so you can get back into the action.