Ha, yeah, he was a fun character.
Anyways. Read your blog post, figured I'd post here.
I like the idea, and it's something I love seeing in games. Chases are fun, but outrunning hazards is even more fun. I love the Doom Ball, Running from a Flood, or even explosions. One of the best scenes I ever ran was a mine-cart chase scene. So, yeah, I like your starting place.
I think my biggest problem is that while the hazard has a lot of stats, and the ability to "surge", which is cool, there's not much PCs can do to modify their own speed. So, it becomes a matter of doing the math, really - if the hazard moves at speed x, and I move at speed y....
I'd suggest a way in the rules for PCs to increase their speed, or at least take shortcuts or something to better avoid the hazard. There needs to be a way in the rules for this to happen.
Secondly, I'm against the use of maps or boards to represent these sort of encounters. Tactical play is useful in a combat - in a situation like this, you should have much more "loosey-goosey" approaches.
I'd suggest four stages of proximty to your hazard. It'd go something like this:
1. Engaged. You are directly in the hazard's area. If it's a doom ball, it's squashed you. If it's a fireball, you're singed. Etc. You suffer the hazard's effects.
2. Close Proximity. You are very close to getting hit by the hazard. Some hazards might have negative effects if you're here. If it's a doomball, there's no ill effect, but if it's a fireball or gas, you could be suffering minor damage or debuff effects or whatever else.
3. Nearby. You are close enough to the hazard to be afraid of it, but not suffering any effects. You're one step closer to escaping it.
4. Clear. You have escaped the hazard.
Now, PCs that trigger a hazard start at stage 2 or 3, and move to get to stage 4 through the use of clever play, skill checks, spells, or whatever else.
Were it me, I'd have all of these stages written down, and put three boxes underneath "2" and "3". I'd then run it like a skill challenge. Each round, each character involved would do something that would help them escape the hazard. If they had a speed of 40 or higher, they'd get advantage on most checks, and 25 or lower would be disadvantage. Something like that. Each time they succeeded, they'd go up one box. Each time they critically succeeded, they'd go up two. And each failure would move them one box closer to "1", or a crit would move them 3 boxes closer to 1.
Of course, I'd play it out a bit more, and make it slightly less skill challenge-y.
My two cents on the issue. Hope it sparks more interesting ideas!
