[HELP] Ending a lua script

[Ezikielth]

Whenever I create a script for an NPC in an Instance and the group whipes, the script doesnt end and when the group pulls the boss a second time he creates a second running of the script and then is 2x as hard because hes running two scrips and spamming. Im using unit: functions.

function Faralash_Enrage(Unit, event, miscunit, misc)
    if Unit:GetHealthPct() < 30 and Didthat == 0 then
        Unit:FullCastSpell(44779)
        Didthat = 1
    end
end

function Faralash_Gouge(Unit, event, miscunit, misc)
    print "Faralash Gouge"
       Unit:SendChatMessage(12, 0, "Fall into your stooper...")
    Unit:FullCastSpellOnTarget(28456,Unit:GetClosestPlayer())
end

function Faralash_Charge(Unit, event, miscunit, misc)
    print "Faralash Charge"
    Unit:FullCastSpellOnTarget(29320,Unit:GetRandomPlayer(1))
    Unit:FullCastSpellOnTarget(30584,Unit:GetRandomPlayer(1))
    Unit:SendChatMessage(12, 0, "Yes, run! It makes the blood pump faster!")
    Unit:PlaySoundToSet(8787)
end

function Faralash_Vanish(Unit, event, miscunit, misc)
    print "Faralash Vanish"
    Unit:FullCastSpell(10389)
    Unit:FullCastSpell(9458)
    Unit:SendChatMessage(12, 0, "Where to go? What to do? So many choices that all end in pain, end in death.")
    Unit:PlaySoundToSet(8791)
end

function Faralash_Garrote(Unit, event, miscunit, misc)
    print "Faralash Garrote"
    Unit:FullCastSpellOnTarget(28456,Unit:GetClosestPlayer())
    Unit:SendChatMessage(12, 0, "Closer now... tasty morsels. I've been too long without food. Without blood to drink.")
    Unit:PlaySoundToSet(8793)
end

function Faralash(unit, event, miscunit, misc)
    print "Faralash"
    unit:RegisterEvent("Faralash_Enrage",1000,1)
    unit:RegisterEvent("Faralash_Gouge",15000,0)
    unit:RegisterEvent("Faralash_Charge",30000,0)
    unit:RegisterEvent("Faralash_Vanish",50000,0)
    unit:RegisterEvent("Faralash_Garrote",69000,0)
end

RegisterUnitEvent(50900,1,"Faralash")

[EcHoEs]

function Faralash_Enrage(Unit, event, miscunit, misc)
    if Unit:GetHealthPct() < 30 and Didthat == 0 then
        Unit:FullCastSpell(44779)
        Didthat = 1
    end
end

function Faralash_Gouge(Unit, event, miscunit, misc)
    print "Faralash Gouge"
       Unit:SendChatMessage(12, 0, "Fall into your stooper...")
    Unit:FullCastSpellOnTarget(28456,Unit:GetClosestPlayer())
end

function Faralash_Charge(Unit, event, miscunit, misc)
    print "Faralash Charge"
    Unit:FullCastSpellOnTarget(29320,Unit:GetRandomPlayer(1))
    Unit:FullCastSpellOnTarget(30584,Unit:GetRandomPlayer(1))
    Unit:SendChatMessage(12, 0, "Yes, run! It makes the blood pump faster!")
    Unit:PlaySoundToSet(8787)
end

function Faralash_Vanish(Unit, event, miscunit, misc)
    print "Faralash Vanish"
    Unit:FullCastSpell(10389)
    Unit:FullCastSpell(9458)
    Unit:SendChatMessage(12, 0, "Where to go? What to do? So many choices that all end in pain, end in death.")
    Unit:PlaySoundToSet(8791)
end

function Faralash_Garrote(Unit, event, miscunit, misc)
    print "Faralash Garrote"
    Unit:FullCastSpellOnTarget(28456,Unit:GetClosestPlayer())
    Unit:SendChatMessage(12, 0, "Closer now... tasty morsels. I've been too long without food. Without blood to drink.")
    Unit:PlaySoundToSet(8793)
end

function Faralash(unit, event, miscunit, misc)
    print "Faralash"
    unit:RegisterEvent("Faralash_Enrage",1000,1)
    unit:RegisterEvent("Faralash_Gouge",15000,0)
    unit:RegisterEvent("Faralash_Charge",30000,0)
    unit:RegisterEvent("Faralash_Vanish",50000,0)
    unit:RegisterEvent("Faralash_Garrote",69000,0)
end

function Faralash_LeaveCombat(Unit, Event) 
Unit:RemoveEvents()
end

RegisterUnitEvent(50900,1,"Faralash")
RegisterUnitEvent(50900,2,"Faralash_LeaveCombat")

There you go