Hairy was about a foot away from the building (he'd just punched the window) and was about 2 meters away from the door.
I'm treating the molotov as an incindiary grenade with reduced scatter and range. Specifically, scatter is 1-3 meters, 1.5 meter 'blast' radius. Hairy dodged, which cancelled out some of your successes and resulted in 1 meter of scatter back towards you and the building. So technically the molotov went off 1 meter from the open door with a 1.5 meter radius.
However, it didn't make sense for him dodging to turn your point-blank hit into you hitting closer to the door than intended, so I'm instead treating it as the gas flowing in your direction. Also, the blast radius of a regular grenade is essentially instantaneous, while the radius of a molotov isn't quite as instantaneous. I could have simply declared that the open door was inside the radius of the molotov and that therefore the inside of your shop caught on fire. However, it seemed more realistic (and more fun) to give you a split second to react and possibly save your shop.
Note that the spread we're talking about isn't the natural spread of the flames after ignition, it's the initial spilling of a couple of litres of flaming gasoline out over the ground
Hopefully that paints a clearer picture.
( )
( / H )
( / x )
---- WD -------=======-------
If it helps, that's a rough diagram of things. Brackets show "effective" blast radius of the molotov, spilling out from the x.