or would this suffice? Timid: Will not fight unless he/she has complete advantage and will run from calls from help due to the danger of being shot?
There never will be any kind of objective criteria, because the term "timid" is a vague one on. Just like in real life, where the labels brave and timid vary enormously between ages & cultures.
On your example: I will run from a call of help if: There is no chance I can get us both out alive and the player just got himself into that situation by doing a very stupid thing. Some players will do, because they feel obligated to "die" together (dumb thing, if you ask me)... or because they simply have FUN trying to see how long they will last (more power to them I say!). But both reasons do make them more brave or less timid.
After 4.5 years, I just fly the way I fly. I will run if the chances are vastly against me, I will try to get alt vs. enemy horde to pick them off one by one, I will use ACK if I have to, I won't up from a vulched field just to feed someone with kills (ok... I actually do the last one occasionally when getting into the "stubborn" mode

).
I have flown that way since the beginning. Subjectively I'm taking the same risk level as when I started, objectively it has changed because I got better and have a better judgement now.
But I'm still timid
