My actual understanding, having grown up in the church, is that ex-members would actually go to the Terrestial Kingdom (tier 2). Though it depends on how you interpret "rejecting the gospel". The distinction depends on if I rejected the gospel or was a good person who was blinded by the evils of the world. The church is a little vague on the subject and I can easily understand an interpretation of ending up in the Tellestial Kingdom (tier 3). It can entirely be interpreted that I rejected the gospel and so am placed into the same category as mass murderers.
In my upbringing it was taught that the only people that went to hell were those that outright rejected the gospel with knowledge, so that puts a lower bound. See Doctrine and Covenants 76[0].
[0] https://www.churchofjesuschrist.org/study/scriptures/dc-test...
Side note: You can only get into the Celestial Kingdom (tier 1) if you accept the Mormon doctrine while on Earth (there are also 3 subdivisions of the Celestial Kingdom that you can move through within the afterlife, but you are not able to move kingdoms).
This just isn’t true that you have to be a Mormon on the Earth to receive the highest degree. We believe you have to have a body to receive your ordinances, but there’s a reason people visit the Temple after they have done their own ordinances and covenants and that is, so they can do temple work and baptisms for those who have passed, and they do this as proxies for the deceased much like Paul taught baptisms for the dead(1 Corinthians 15:29).
> It can entirely be interpreted that I rejected the gospel and so am placed into the same category as mass murderers.
That doesn’t necessarily mean it’s a bad place though. (Also if you choose to never accept Christ until the final resurrection then that’s your choice, but I don’t think you’re doomed to it). Here’s a quote from that D&C 76 about the tier 3 as you called it or the telestial as it’s called there:
> 89 And thus we saw, in the heavenly vision, the glory of the telestial , which surpasses all understanding;
> 90 And no man knows it except him to whom God has revealed it.
So, the glory itself exceeds all understanding it reminds me a lot of 1 Corinthians 2 particularly 9 & 10.
> 9 But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him.
> 10 But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God.
I think we’ll all come to see God’s and Christ’s great mercy at the Judgement seat.
I'm not trying to make the point that there isn't pressure on people to stay in the church. I know nothing whatsoever about the LDS church. People that say there's pressure, I believe them. I'm just making a nerdy theological point about "Hitler-salvation" as a threshold.