Christians can fall away. And those who have rejected the Church of Christ have fallen away

DS:No Christians can leave or be outside of the church since we are the church.

Christians can fall away. And those who have rejected the Church of Christ have fallen away from the Church and Christ.

1 Timothy 1:18-20
King James Version (KJV)
18 This charge I commit unto thee, son Timothy, according to the prophecies which went before on thee, that thou by them mightest war a good warfare;
19 Holding faith, and a good conscience; which some having put away concerning faith have made shipwreck:
20 Of whom is Hymenaeus and Alexander; whom I have delivered unto Satan, that they may learn not to blaspheme.

2 Peter 2:21-22
King James Version (KJV)
21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them.
22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.

You don't know what the church is or how one enters it so there's a good chance that you're not in it just like most of your deceived fellow Catholics who believe the false gospel you've been taught.

It is totally the reverse. It is you who possibly are not in the Church since you deny Baptism:

Mark 16:16
King James Version (KJV)
16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned.

False gospels don't save.

The Protestant gospel is a false gospel.

No salvation = not in Christ's church.

Exactly.

Salvation = automatic immediate entrance into Christ's church.

Perfectly true. But you are not the Judge of your salvation. God is:

1 Corinthians 4:4
King James Version (KJV)
4 For I know nothing by myself; yet am I not hereby justified: but he that judgeth me is the Lord.

We will all stand before the Judgement seat of Christ. Including you:
Romans 14:10
King James Version (KJV)
10 But why dost thou judge thy brother? or why dost thou set at nought thy brother? for we shall all stand before the judgment seat of Christ.

Where you will be judged according to your works:
Revelation 22:12-15

King James Version (KJV)
¹² And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be.
¹³ I am Alpha and Omega, the beginning and the end, the first and the last.
¹⁴ Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
¹⁵ For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie.

Sincerely,

De Maria