A common piece of advice to GMs is to keep a copy of all your players' character sheets as handy reference.
Of course this doesn't always help if the character build is so complex that you can't readily tell what the result will be for any given game situation.
[Reminder: Our guest commentators have not seen Rogue One. Part of the fun is seeing how their untainted impressions re-interpret the movie through the lens of our comic.]
Even without Dodge, a saving throw should allow you to save for half damage. Pete would only have taken 8 points of damage, and would still be up and alive.
But seriously, only 9 hit points? Is that one per level?
And... a glass cannon? An invisible glass cannon? Massive damage, and relying on "never being hit" when you have a 1-in-20 chance of being hit at any time from normal attacks? When standard campaign behavior is that you will have something happen, at some point, that does damage, be it fall (Episode II), knock-out gas (Episode I) (and captured, tortured, etc - Episode V), being shot at from all sides (Episode III?), big massive explosions all around you (I, IV, and VI), or just plain being backed into a corner and forced to either jump to your doom or be hacked to bits (lost count of all the times :-)
Hmm, when did we see that "enhanced challenge rating of a later encounter" that we were told about at the beginning of the campaign?
GM: The fuel explosion is only 4d6 damage.
GM: You avoid all of it, right?
Chirrut: Oh, Dodge doesn't work if all adjacent hexes are in the explosion.
GM: Well then. <roll> 16. Apply your armour reduction.
Chirrut: Let's see... robes. Explosion damage. That'd be zero.
GM: Okay, take 16 damage then. Meanwhile—
Chirrut: Um, wait. I only have 9 hit points.
Chirrut: No, total.
Bria: But you just levelled up twice!
Chirrut: I have a -4 Con modifier! I just don't get hit! Until now.
GM: Okay, so you're on -7. Baze can stabilise you.
Chirrut: Actually... I took Haemophilia so I could get Extended Extended Reach. I can't be stabilised except at a Level 4 medical facility.
Chirrut: Sorry guys. You're screwed now.