Reacting to and manipulating the voice lines that play during the run is a key part of running any route.
When a voice line is triggered while another voice line is playing, the behavior depends on the source of each of the two voice lines.
Some voice lines, such as the voice line from failing to summon, will queue up behind the current voice line(s) and play once those lines finish. This can make your RNG manipulating timing-dependant. For example, if you summon while Chaos is speaking after selecting their boon, you won’t get the increment from the failed-to-summon voice line until Chaos finishes speaking, and if you exit fast enough you won’t get it at all.
Other voice lines, such as those spoken by Chaos after selecting a boon, won’t play if another voice line is playing. In these cases, you can often intentionally block the voice line and its RNG increment. For example, you can trigger a failed-to-reroll voice line on a Chaos boon and then select the reward while it’s playing, and this will prevent Chaos from speaking at the end of the room.
Many voicelines have cooldowns. The timer for these cooldowns keeps running in many circumstances where the IGT is paused, for example in Boon or Well Shop menus. This means that more or fewer voice line rolls may be triggered depending on how fast you run the route RTA. In some cases it may be required to wait on a menu for a cooldown timer to expire, if you need the voice line to stay on route.
You will usually get different items from rerolling a well shop depending on whether pressing the reroll button triggers a voice line. You can usually affect this by triggering another voice line to play while the reroll is happening, or not, as desired.
In rooms with more than one exit, there is a chance that Zag will speak a line when he approaches the exit for the first time. This will occur at most twice per run:
This voice line does not queue, so it can be blocked by triggering the failed-to-summon voice line as you approach the door. However, if the voice line is blocked in this way, it will still be eligible to play later in the run.
In Asphodel, there is a roll for a voice line to play on room exit (via a boat). This voice line can only play once per run, so once it has triggered, you won’t get the RNG increment any longer. The voice line can be blocked by other voice lines; if it is blocked the roll will still happen in later rooms.
When a Chaos gate unlocks, there is a chance that Chaos will speak a voice line beckoning Zag to enter, but only if Zag is at or over 50% health. This voice line can only play once per run. This means that:
If you attack or cast at an NPC (such as Nyx in Chaos rooms, or Charon in the shop), this can trigger a reaction voice line, and therefore causes one or more RNG increments.
Charon will groan if you approach within a certain radius of them, which counts as a voice line and also triggers RNG increments.