I agree that the overall win depends largely on the whole team and not just one player (at least that's how it is in a good game). That said, I'll admit how I enjoy diving, solo, into group of enemies and taking out whoever I can in the confusion. Sometimes it can be fun to be that 'everyman-hero' (so long as you're good at it).
Hell, not just sometimes. Most of the time I do this.
My first goal is to rush their base. I can either sneak past the turrets or test to see if they're working while at the same time setting them up for the next rush. If they happen to be moving the reactor then I can pass the word onto my teammates and proceed to bite some head. Either way my first goal is to dive into that base and get as many kills untill a handy defence takes me out before any human can. Rinse and Repeat. If you're feeling particularly evil, you can use a goon to get long chains of kills before being turreted.
I do this for those fun few seconds I spend dodging turrets and biting/slashing/chomping heads. It's that sort of action that I love about tremulous. The kills I normally get, give my team an advantage in the form of higher stages and any evos I share. This helps them. That alone won't win the game for us though. What they're doing while I'm doing what I do plays the larger role (unless things go a little too well and I end up taking out the nodes in the first 2 minutes =/).
To those who dislike 'kill-whoring', I guess it's unlucky that it's so gosh darn fun to try for the most kills. I'm not sure if you'd call what I do 'kill-whoring' though, as I hate to camp round corners/on turrets and when I have an opportunity to end the game I'll take it (thereby limiting how many kills I would achieve.. unless counting by kills per minute).
All in all, the kill count never means as much to me as how hard it was to kill the people I did. Being a challenge seeker, I'd far rather get 3 pro kills than some huge number of n00b kills.
Edit: That was with aliens.. I do a very similar thing with humans, but it can be hard to stay in that base long as I'm not fast moving evading slow turrets anymore.. I'm slow moving picking off tubes and preferably eggs from a distance. The most exciting thing about that is the aliens that spring unexpectedly round the corner.
Just pounce over them and look up
I think you mean look down. ^^
Edit: If you meant to show how not looking at them while colliding does no damage then saying "jump over" isn't helpful. ^^