Swift Action & Initiative Question

[EnragedHalfling]

Player X is playing a ninja, wants to execute a "swift action." His initiative is after a monster (i.e. monster goes first and then the character). Can the PC execute his swift action before the monster's initiative or does the PC have to wait until it is his (the PC) turn?

Example: Evil magic user goes first in initiative order. She wants to cast a magic missile at the party and chooses to target the PC ninja. As a swift action, the ninja can turn invisible for 2 rounds. If he can execute his swift action at anytime, she would have to target another party member. Is this accurate or does the ninja have to wait until it's his turn to execute his swift action?

[Lamontius]

A Swift Action can only be used while it is that player's turn to perform actions, in the proper initiative order.

An Immediate Action is like a Swift Action, but can be taken at any point during that round.

If the ninja's ability is specifically called a Swift Action, not an Immediate Action, then they can only perform that ability when it is their proper turn in the initiative order.