Is Mortal Sin a Sort of "Lightbulb" Salvation?

In having a dialogue about mortal sin here, the objection was raised that this is a sort of "lightbulb" salvation, where one moment it is on, the next it's off. One moment you are saved, the next you are not. This sort of salvation was said to be unbiblical. There are two problems with this, the first being that Catholic theology doesn't look at it this way. From our perspective, with our human minds, the linear "first you're saved, then you're not, then you are again" is actually correct and biblical, but Catholic theology does not limit God and force Him into our human understanding of time. In reality, how this would work is much more complicated than we could understand. So the short answer is, it's not a sort of lighbulb salvation.

However, the fact is that salvation as an on again off again thing is quite Scriptural. I posted this example over there, and I thought it would be beneficial for you to see here. If you want to see the entire dialogue, read the comments over at the other site. Here you go!

Again, I would not call it lightbulb salvation, but if you want to, I have Scripture for that.

Mat 10:32 So everyone who acknowledges me before men, I also will acknowledge before my Father who is in heaven,
Mat 10:33 but whoever denies me before men, I also will deny before my Father who is in heaven.

Mat 16:25 For whoever would save his life will lose it, but whoever loses his life for my sake will find it.

Ok, that premise is clear. A little later in Matthew:

Mat 26:33 Peter answered him, "Though they all fall away because of you, I will never fall away."
Mat 26:34 Jesus said to him, "Truly, I tell you, this very night, before the rooster crows, you will deny me three times."
Mat 26:35 Peter said to him, "Even if I must die with you, I will not deny you!" And all the disciples said the same.

Now we have another premise that strengthens the first: Christ equates denying Him with falling away. Not only this, but the parallel is drawn in that Peter denied Christ to save his life, whereas Christ says if one did that he would lose his life. When Peter denied Christ to save his life, he did not physically die, so earthly life could not be what Christ was talking about, though very few, probably mostly modernists and demythologizers, would have tried to say that it was anyways. So we have a few premises:

1) Whoever denies Christ, Christ will deny Him before the Father
2) Peter denied Christ

Conclusion - Christ denied Peter before the Father

or

1) Whoeve would save his life over Christ will lose it
2) Peter saved his life over Christ

Conclusion - Peter lost his life

There are plenty of other ways to put this, and it is even more obvious without having to use my syllogisms because there is a lot more evidence, even in this post, then I have put into the syllogisms. In Luke, Jesus says to Peter:

Luk 22:31 "Simon, Simon, behold, Satan demanded to have you, that he might sift you like wheat,
Luk 22:32 but I have prayed for you that your faith may not fail. And when you have turned again, strengthen your brothers."

So Peter was going to turn back, and as we know he did. Here is what we know:

A) Whoever denies Christ will be denied before the Father
B) This is the same as falling away
C) Whoever saves his life over Christ will lose it
D) Peter denied Christ and saved his life over Christ

Conclusion - Peter lost his life and fell away, and would be denied before the Father.

If he had died that moment, he would be in according to the Bible.However, Christ says that he would turn back. Turn back from what? From his denial. He did, in John 21, where Christ asks Peter if he loves Him three times. If Peter had died after this, we can be pretty confident that he would have gone to heaven.So here we have a clear, unambiguous case of 'light-bulb' salvation.