Trusting in his magic, Cadeyrn shouted out "Cheeearrrrrrrrge!!!!!" before running up the stairs slightly and throwing both of the bottles up to near the top of the stairs.

Spoiler
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Move action to place Cadeyrn 5 feet onto the stairs. Hero point then spent to use two standard actions to throw both bottles 10' up the stairs, the one on the left five feet to the left (aka, side by side, each aimed at a different square).

Bottle one (against touch attack ac): (1d20+4)[22]
Bottle two: (1d20+4)[9]
Damage bottle one (1d6)[5]
Damage Bottle two (1d6)[6]

There's an additional 1 damage done to all enemies within 5' of the one struck, presuming the attacks work (thus, if both bottles hit, the two struck by the bottles will take 1d6+1 damage instead of just 1d6). Also, if bottle 2 is technically 15' away since it is to the left, then it is at a -2 to attack. Finally, if the attacks work and the zombies do not put out the fire on themselves, they will take an additional 1d6 damage next round (presumably the fire burns out after that as it doesn't say anything in the alchemist's fire section on that, but you can obviously use your best judgement on this one, Samshiir).