Could (spoiler) have distrupted the design? Spoilers for all FD endings.

Sorry this will be long.

I was writing a thread for the Final Destination 5 board about how that movie (and possibly TFD) is the only one that has a canon explanation as to why Death waits for a longer time before killing the final survivors - in the fifth movie, we are introduced to "Kill or be Killed", where someone on Death's list can steal the lifespan of someone not on the list by killing them, or at least causing their death. This gives a clear reason as to why Death had to wait; the remaining characters on Death's list have someone else's lifespans, so Death has to wait until the day those lives were supposed to end to kill the survivors. However, Death always waits, and I was never really sure if it was an intentional thing (like Death is purposely waiting until the survivors have let their guards down), or if something the survivors did some how distrupted (but not destroyed), Death's list, forcing Death to wait until things got solved.

The only FD that I couldn't ever come up for a theory for as to explain why the design could be disrupted was Final Destination 3, as Wendy didn't do anything out of the ordinary to affect the list. Alex saved Clear by directing Death to him, in a sense (it wasn't just that he saved her, but the way he did it could have killed him), Kimberly drowned herself, and was revived, the survivors of The Final Destination were supposed to die at Death by Caffeine anyway, but if they weren't, it could have been Nick saving all those people at the mall could have disrupted the design somehow. Final Destination 3 was the only one I didn't get, as all that happened was that Wendy got skipped, so why should that make Death wait to kill her, Kevin, and Julie?

Then I thought of something, as I typed that I still didn't know exactly what was supposed to kill Wendy, but that I did know that it was probably either the firework, the sign, or Ian like Wendy thought. If it was the firework, then Wendy saved herself, if it was the sign, then Ian may have inadvertently saved Wendy, and if it was Ian, then I have no idea what happened, unless Ian took too long to kill Wendy so Death killed him, which doesn't really make sense to me.

However, I realized that I may have already found the answer in something I said earlier with the first movie; Alex put himself in Death's path, he didn't just save Clear, and then get hit by another accident, he put himself in the path of Death to save her. With this in mind, let's assume that the McKinley sign was what was supposed to kill Wendy, but Ian saved her by unknowingly stopping her from getting in the path of the sign, so she gets skipped, however, Ian did this partly by standing in the path of the sign himself, which killed him. Let's say putting yourself in the path of a possible death, or attempting your own death when you are the next one to die, after the current victim, can somehow affect the design? If you, or someone else simply saves the survivor before you, then Death simply skips them, and kills you. However, let's say you put your own life at risk, like Alex did, or blocked whatever was going to kill the previous survivor like Ian may have inadvertently done, and lets also say that has an affect on the design, like one that disrupts it so badly, that Death has to wait before starting the design for those victims up again.

With that in mind, could it be possible that Ian was the reason that Death had to wait before it could continue killing? While Ian did not intend to sacrifice himself (he was ready to end Wendy's life, and had no intention of dying), did he accidently do that, by blocking the sign that was supposed to kill Wendy? Did him unwillingly putting himself in Death's path, and saving the previous victim cause problems with the design, the same way Alex purposely attempting to sacrifice himself for Clear did?