If you look at the original rules that came with Underhive, you'll see a *much* more sensible version!
1. Test to see if flames go out first! 6+ base, with the usual bonuses for nearby friendlies and a double action to drop & roll.
2. If still on fire, take the hit.
3. Run around like crazy.
It's SO much better to use the original version. This way you can actually send people to help your blazing fighter first. Wonder why they decided to screw up a perfectly good rule?