Can you really spend fate points on requisition rolls?

When a character or enemy fails their agility test to not be set on fire from a flame weapon do they immediately take 1d10 damage? if not when do they take it?

Why do (I forget the name sharpshooter, gunslinger?) Las weapons do so much damage? Like 1d10+7 seems like alot close to a bolt pistol I think right?

Requisition tests: yes. To see all the details and limitations on fate point usage (pg 293) it tells exactly what can can cannot be done.

When a character catches fire on their next turn, at the begining of their turn, they are on fire and suffer all the ill effects of it. This includes damage, fatigue and probably WP tests, need to be done before anything else on their turn can begin.

I assume you mean the Hot-Shot Laspistol or gun which does 1d10+4 Pen 7. They are quality weapons, the pinnicale of the small arms laz weapons. They can be further modified by to do more damage or have diffrent effects if proper equipment is gathered. They are powerful enough not only to kill most humaniods but even take down space marines (refrence from tabletop) and other powerful and heavily armored things. I would say their biggest weakness is their overt nature; they require a backpack powersupply and I would argue not possible to hide.