Explain 2 things to me, if possible:

Zack feels like a fifth wheel after Api turns up, it's clear the women likes Api more and doesn't see Zack as a potential Adam to her Eve.

He sacrifices himself in the hope they will have a better life without him.

"- How did he managed to drive it anyway, if there were high radiation levels, which would trigger the explosives?
- Even if he remote controlled the truck, it still would have been in danger of exploding too early.
Was that problem even adressed?"

That wasn't specifically addressed, no.

But Zac says, "The labs so hot with ionization, it would be like driving into a microwave oven." I'm not scientist but what I got from that statement was that it would be potentially dangerous to drive the truck in. Not that the truck would *DEFINITELY* explode the second it started driving towards the lab. It was risky. But there was no guarantee that the truck would explode before they got there. And, aside from the remote control idea, they really didn't have any other option but to drive the truck in.

"But didn't the Effect needed to happen later?"

Thats a little ambiguous. Zac predicted the effect to occur at a specific time. But there is a strange, surreal disturbance at one point in the movie where Joanne says, "you're calculations are wrong, its too soon" to which Zac replies, "that was just a tremor, next time it will be the real thing" But Api apparently is very skeptical of Zac saying, "you're calculations are a waste of time"

I think the point there was that Zac might have been a little arrogant. He made predictions but there was no way of really knowing for sure. They also mention earlier in the film that the character of Perrin "threw the switch" at the beginning of the movie causing the effect to occur. Zac says, "Our little effect is now happening tomorrow morning. But there's no Perrin. And no switch. So maybe the effect and the grid (at the lab) are totally unrelated!"

So even Zac admits that there's a great deal of uncertainty regarding why the effect happened, why it was going to happen again, and precisely WHEN it would occur.

I don't think Zac knew the effect was going to occur right when it did. I think it most likely occurred early.

Korabljenik, I hope to answer both of your questions:

Did Zac lie about the danger? No. On top of the radiation indicator's flashing light and alarm, he drove recklessly to stop Api from getting too close to the lab, suggesting the danger was real, but not certain.

Driving the explosive filled truck was a calculated risk. Zac knew that the effect, which made the living die (or vanish), would repeat "tomorrow morning." Morning was approaching, and he did not want to be responsible for more deaths (i.e., Joanne and Api) and sought to take down the grid to prevent the second effect. Accordingly, he gambled by driving the truck to the satellite dish, just hoping to get there and not explode prematurely. There was no time for any other option.

The question about the timing of the effect is critical to enjoying the brilliant, delicious, unmatched irony of the film:

Zac only survived because he committed suicide TWICE.

He failed to blow up the instillation before the second effect took place. The effect and Zac's detonation were simultaneous, thus he 'died' at the instant of the effect a second time.

Did that answer both questions?

Side Note: Korabljenik asked about the specific time of the effect, which at the start of the film was 6:12. If one 'translates' that time code from the digital clock into a Revelations chapter and verse, the resulting text references a "great earthquake" and "moon turned to blood red," looking like the film's audio and graphic representation of the effect.

It's never suggested that the radiaton would set off the explosives.

It's a given that the radiaton would contaminate any life form exposed to it, and any of their offspring would be most likely mutated, if they would be capable of reproducing at all.

Since both of the assumptions are incorrect, the questions are moot.

No one actually says the explosives will go off, only that it would be unsafe for the humans to drive further.
And we can't assume that the effect that occurred as Zac drove the truck was the final effect or just another tremor, not that it mattered, since he set off the bomb anyway.
Zac may have predicted the event wrong, but his only lie was that he was going back to town. He was certainly always going to sacrifice himself, and for the same reasons he tried to commit suicide in the beginning. He felt responsible.

1. Gamma radiation cannot cause explosives to detonate unless the explosives are configured in such a way to make them vulnerable, but it will destabilise them over time and that is never good with any volatile substance. Gamma radiation has been known to break some explosives down in to gases which can then be ignited, or to cause crystal formations that make explosives extremely sensitive to movement, but either of these things would take time.

In short, simply driving the truck up to the place would only have an effect on the driver in the short term, not something to worry about if you are about to detonate the explosives manually. He was lying to them again in order for him to go back and deliver the explosives alone.

2. I don't think they wanted the effect to happen again, but even if it did (which I suppose we witnessed) he had atleast destroyed the antennae so the effect may have been local, ie. only affecting him and not the whole planet, or only affecting the Earth and not the whole universe.



You don't know sh!t, Jon Snow!

I think Zack knew it the effect would happen again. And it was obvious he was quite jealous of Api. Maybe he hoped Api would die and hewould get a redo with just him and Joanne lol. Who knows.