question about PetAttack code

[zakiya]

The part in red is what I can't figure out

if ${Me.Pet.Target.ID} != ${KillTarget} && ${Actor[${KillTarget}].Distance}<${AssistHP}
{
if ${Me.Pet.Target(exists)}
{
EQ2Execute /pet backoff
wait 2
}
target ${KillTarget}
wait 1
EQ2Execute /pet attack
wait 30 (${Me.Pet.Target.ID} != ${KillTarget})
if ${PetGuard}
{
EQ2Execute /pet preserve_self
EQ2Execute /pet preserve_master
}

If I read it correct, the script is comparing MA HP to Target distance ? Could someone explains to me about this ?