Truth-telling: What do you do when ally and enemy are both in your line of fire?

I get V-8 ready then

90 % of the time I would just kill both. If we are away from medic or main battle lines I would try not to shoot or try to preposition.
Medics heal fallen allies so np.

Take the freaking shot. If I'm dancing with the devil,purple ones that is, please shoot and ask questions latter. If I die no biggie. They don't charge me to re-spawn. Not yet at least.

I just hold the trigger.

I try to not hit friendlies as they still block bullets but if they run in the way I don't give a sh**. It's not like there's really any punishment for killing a friendly once in a while

I aim more carefully.... take precision single shots, so that if I do hit friendly it's not for a lot, but I do weaken the enemy if I hit him. Mostly I can avoid hitting friendly entirely. That way if friendly in front of me drops first I have some head start vs enemy, and if enemy falls first then there's no problem there.

People that I TK by shooting are accidents of when I am full spraying enemy and they get in the middle while already low health to begin with. The "Stop firing I'm a friendly" scream along with distinct sound of hitting friendly is enough for me to stop shooting them almost immediately. Few bullets will get through, and they will die if low health already. Most players do something similar, I die to friendlies more often than I kill them (statistically from planetside.tk 2:1 ratio get_killed:do_the_killing), which might be once per hour. Largely depends on type of fight, could be a bit more often in very crowded and confusing fights.

Most friendlies I kill are squadmates, same for people that kill me. Planetside.tk is a good statistics site about tking.

Used to hold fire. Or if I could get a shot with minimal risk, I would take it. But after so many shots in the back by fellow TR (mainly by rocket primary noobs kill stealing), or ******* running in front of MCG on full spin, or TKs by the dumb ***** who don't know what a fellow TR looks like, and especially MAXs who hug choke points like they are the only one that matters (instead of pulling back and allowing more fire lanes on the choke point). I go full auto and shot both of them full of holes.

Let me add another one:

You're at a flag and several enemies are rushing towards a chokepoint that also has a friendly in it. Do you toss the anti-personnel mine into the chokepoint and duck out of the way to hold the point?

Do you throw a grenade after it just to be sure?

Depends on my loadout/class.

If a sniper - I cloak and move on.
If a LA - I jetpack to a better vantage point
If a Heavy/engineer - I open fire and /try/ not to hit the friendly or lob a grenade
If Medic - I open fire and don't give a damn as I can rez them if I kill them by accident

if there are more enemies than friendly then yes.