Is there time after a free action triggers to use another free action before continuing?

Question

I've got the following feat and power on my rogue.

Slaying action:

If you spend an action point to take an extra action and have already dealt Sneak Attack damage during this round, you can deal the extra damage a second time during this turn.[MP:139]

Press the Advantage:

rogue attack 1
Daily ✦ Keywords: martial, weapon.
Free Action.
Trigger: an enemy becomes bloodied by a melee attack from the user.
Target: the triggering enemy

Since both the power and spending action points are free actions, can my rogue deal sneak attack twice to the target under the conditions that

1. They are in melee range of the target and have bloodied that target with a melee attack and
2. They spend an action point between the triggering attack and Press the Advantage?

Or is there no "between," even for free actions?

Answer 1

Yes, you may, so long as you haven't performed any other free-action attack this turn.

Free Action

Normally, characters may take an unlimited number of free actions to do anything other than use an attack power, but this can be limited at the DM's discretion. In addition, the July 2010 update limited characters to one free action attack power per turn.

Burning the Action Point is not a free-action attack, and so you are free to use Press the Advantage. I imagine the sequence of actions to be:

1. Rogue performs a standard-action melee attack on Target, and bloodies Target.
2. Rogue spends Action Point as a free action to gain an extra standard/move/minor action.
3. Rogue now has an extra standard/move/minor action, a free-action attack, and a reasonable amount of other non-attack free actions.

As you can see, at any time after Step 2, you can use Press the Advantage - either before or after you take the extra action generated by the Action Point. ^_^

Answer 2

TL;DR

Triggers follow an order of operations. Free actions have different "speeds" at which they go off.

All free actions occur as timing of Immediate Reactions unless they must function as Immediate Interrupts in order to exist

My understanding of the rules based on asking the GM afterward:

It's all about the order of things.

Standard: Hit with SA (SA used)
AP: Free (Recover SA)
Standard: Hit, bloody target
Free: Hit (SA used)

That one works because triggers are taken when they come up.

Standard: Hit with SA (SA used), Guy bloodied
Free: Hit (No SA available)
AP: Free Action
Standard: Hit (SA used)

This worked this way because

when a trigger happens you almost always have to use that trigger immediately unless you are obeying another trigger that happens at the same time.
Shift 1 square and make a melee basic attack when you kill an enemy
and
Make a charge attack as a free action when you kill an enemy
Can be done in any order, but you have to use them or lose them.
So you can shift 1, hit, then charge or you can charge, shift 1 and hit. You can't do anything else before or in-between those or you lose the triggers you didnt use.

Another couple of examples to clarify this stance (which I'm not claiming as my own yet, it's how this campaign will run though so I accept it that far at least).

Free Action
Trigger: You are damaged
Effect: You gain 10 temporary hit points
take all the damage, then gain temporary hit points.

Free Action
Trigger: You are damaged
Effect: You gain resist 10 to the triggering attack
reduce the damage of that attack (Because it makes no sense otherwise)

This is the general rule to which there are a couple of exceptions, not including Press the Advantage and Slaying Action.