Trip with reach, 5-foot step, and Vicious Stomp

[Kazaan]

In the course of a discussion, we came against the following situation:

Point: You can trip someone with a reach weapon, take a 5' step up, and perform a Vicious Stomp AoO against the now adjacent opponent.

Counter-point: AoOs resolve before the triggering action and interrupt the normal flow of combat so can't benefit from the AoO granted by VS because the opportunity was already lost due to being too far away when it happened.

Which is correct, officially?

[Carbon D. Metric]

No, the 5ft step is not instantaneous sadly, and therefore occurs after the triggering step of the them being knocked prone, which happened when you were 10ft away.

sadly.

[Kazaan]

Is there anyplace where that is clearly and officially cited?

[Starglim]

Vicious Stomp wrote:

Benefit: Whenever an opponent falls prone adjacent to you, that opponent provokes an attack of opportunity from you.

The opponent was not adjacent to you when he fell prone, so he doesn't provoke an AoO due to this feat.

Note that Greater Trip works differently, since the victim provokes for being tripped and does so in any square that an opponent of the victim threatens. Further, if you Greater Trip an opponent with a reach weapon and your buddy adjacent to him has Vicious Stomp, said buddy can take two AoOs on the victim, since he provokes twice for different reasons.

[Kazaan]

I seem to remember one of the devs (maybe JJ) stating that a 5' step can be taken "as part of another action" since it is, in itself, a non-action. By doing so, could you, say execute the trip maneuver at reach and taking a 5' step simultaneously to position yourself adjacent to them when they fall prone? I just want to cover all angles at which the position could be attacked before I drop the hammer.

[Komoda]

You are correct about taking a 5' step as part of an action.

However, it is still to late. The trip causes the fall prone, instantly.
Then you 5' step.
By then, they are already prone and it is too late to stomp.

[MyTThor]

I think it's pretty clear that they are on the ground before you're adjacent to them.

[Shfish]

An interrupt happens before the triggering thing occurs, and an AoO is an interruption. So when the trip occurs you are too far away to vicious stomp them when the triggered the AoO.