After skipping the Training Camp, the first mission offers two routes to enter the enemy compound. In both cases, I have to follow a guide as I approach it, so there's a short scripted sequence that cannot be skipped. (If you run ahead of the guide, he waits for you to come back. If you don't, a crucial mission goal is not fulfilled and you can't finish the mission.) Shooting starts at around 4 minutes into the video.
I used the "back door" route with the wire cutter. This route takes roughly the same time as the frontal attack, but I don't have to kill as many enemies. What's more, I end up at the favourable end of the camp: I just have to go through the enemy base and do what has to be done in this "kill them all" mission. The other route would require going through the camp twice.
I let the dog wound me a couple of times (and not just in this mission) because the more I heal myself, the better medic I become -- this skill is indispensable in later, more heated missions.