Triggered Abilities during resolution

[Valtrix]

I forgot exactly what happens for triggered abilities while a spell/ability is resolving. Consider the following example:

I Genesis Wave for X = 3. One of the three cards I reveal is an Eternal Witness. Witness enters the battlefield (as Genesis Wave is resolving) and its ability triggers, and if I recall correctly the ability can't be put on the stack until the genesis wave finishes resolving. After genesis wave finishes resolving I declare targets for witness and move its triggered ability to the stack. Since I had to wait until genesis wave finished resolving I can now target the genesis wave which is in my graveyard.

Is this the correct sequencing? I really just can't remember exactly about when triggered abilities get moved to the stack exactly.

[cdr]

Abilities can trigger at any time. Any outstanding triggers are put on the stack (which is when targets are chosen) the next time a player would gain priority.

Begin resolving spell, spell makes things enter the battlefield, ETB triggers trigger, spell finishes resolving and goes to the GY, priority is about to be regained so triggers get put on the stack.

http://www.yawgatog.com/resources/magic-rules/#R603
603.2. Whenever a game event or game state matches a triggered ability's trigger event, that ability automatically triggers. The ability doesn't do anything at this point.

116.5. Each time a player would get priority, the game first performs all applicable state-based actions as a single event (see rule 704, "State-Based Actions"), then repeats this process until no state-based actions are performed. Then triggered abilities are put on the stack (see rule 603, "Handling Triggered Abilities"). These steps repeat in order until no further state-based actions are performed and no abilities trigger. Then the player who would have received priority does so.

[TsumiBand]

Abilities can trigger at any time. Any outstanding triggers are put on the stack (which is when targets are chosen) the next time a player would gain priority.

Begin resolving spell, spell makes things enter the battlefield, ETB triggers trigger, spell finishes resolving and goes to the GY, priority is about to be regained so triggers get put on the stack.

http://www.yawgatog.com/resources/magic-rules/#R603
[font=courier]603.2. Whenever a game event or game state matches a triggered ability's trigger event, that ability automatically triggers. The ability doesn't do anything at this point.

Emphasis mine -- I think this is the relevant part of the discussion, yes? The trigger, or the 'act of triggering' or whatever you want to call it, is different than the ability being placed on the stack.

I think people tend to think of a triggered ability as instantly 'appearing' on the stack, which means that it could happen at any point - during the untap step, during the resolution of a spell or ability - but really, as far as I can tell, the trigger is almost more like a 'note' the game leaves itself: "The next time I (the game) check state-based effects, make sure I put [this ability] on the stack!" In this way the game isn't interrupting itself when it tries to resolve effects; everything still happens in the intended order, and you don't just start resolving something else in the middle of resolving the actual trigger for the event.

A good example of a time when the game needs to forgive itself for actually putting something on the stack while something else is busy resolving is Isochron Scepter. The Gatherer rulings say (among other things) - "You cast the [copied spell] while this ability is resolving, and still on the stack. Normally, you're not allowed to cast spells or activate abilities at this time. Isochron Scepter's ability provides an exception." Years ago, the last sentence was much more blunt; it said "Isochron Scepter's ability breaks this rule."