This is my take and .02, for what it is worth.
Basically to me, that always meant you take EVERYTHING they do/say with a literal grain of salt; because after all, this IS MLC, where anything and everything can happen...and to keep the confusion down within yourselves, it's best if you believe NONE of of what they say, and only HALF of what they do, bearing in mind that even that HALF could "reverse" itself AND its position at ANY given time.
Once I got a good handle on it; figured it out for certain; I actually learned to NOT even believe ANY of what I was hearing/seeing, as it was ALL SO unbelievable....it wasn't until he navigated past the affair, finished Other Woman Withdrawal, and turned back toward me to try and start repairing at least some of the damage that I started seeing better consistency in his words and actions again; but this even was slow to come..I still found myself bearing more than my share of responsibility of making sure the household was run the way it was supposed to be in his "absence" of mind.
They SAY alot of and a great many EMPTY things that really mean NOTHING; the vast majority of MLC'ers are blowing nothing but "hot air" and don't intend to really follow up unless FORCED to by the LBS; that's why you can't believe ANYTHING of what they say.....for example, they may very well threaten to move out, or even file for divorce, every time the LBS cries, begs, gets angry, is argumentative or whatever.... and keep running off at the mouth in the same type of threat, until called on it, and told that IF that is what THEY want to do, do it, but stop threatening; using this type of a boundary or the LBS actually shows them the door; which I DON'T recommend, because ANY life changing decisions like that SHOULD stay on the MLC'er.
Honestly, I STILL fail to understand where some think that YOU know what's best for them, because that makes you just as much of a controller as the MLC'er when you take a decision like that from them. In a NORMAL situation, I really could understand; but MLC is a different animal entirely.......remove yourselves from the room, and their presence for a time, once you give them that kind of choice of leave or not leave; but don't remove yourself or them from the house, and simply leave them to their own devices, they will figure it out or they won't.
On a side note, I've been told a number of times by others that throwing them out or not, depends on whether they are taunting the LBS in certain circumstances when a MLC'er is within an affair, public affairs, things like that, and I still don't advocate throwing them out during MLC; but making them leave just because you get tired of them threatening or otherwise, CAN backfire on YOU, especially, if your intention is to stand for your marriage; as something as small as PRIDE really can prevent some of them from returning; and you may NOT get another chance to pave the way for their return, that's a chance you take.
And if they do return, it's sometimes because they are the "clinging boomerangs" that RCR so often speaks of in her writings.....Me, I see a return being orchestrated by the Lord who intervened within the situation, to keep His Will from being circumvented........just so you know, I was WARNED by the Lord in my own case NOT to throw him out; to keep that decision on my HUSBAND'S shoulders, that if I threw him out, it WOULD have been a "controlling" move on my part, NOT to mention he would NOT have returned, because of this little thing called PRIDE that he had as a monkey on his back. Not to mention the fact that I would have been charged with the responsibility for my actions in that aspect, and consequences would have been dealt and meted out to me....and I did recognize the controlling nature of me vs keeping in on him..so, I did what I was advised/instructed to do...as I did not want to bear this blame on me..once I laid the boundary mentioned above, he shut up, and didn't threaten me again, I had taken the ammunition for his justification AWAY from him.
Half of what they do is a tricky proposition, because you honestly don't know for sure IF they will follow through on what they tell you they will do..it's a 50 percent chance they won't do anything, or 50 percent they will.
On the other hand, you may see them move out, only to ask to come home, or even just show back up at home, the next week, or even the next day; or they may tell you their "feelings" has changed, and in action, they are cold as ice, the next time you see them, they are hot as fire, and very affectionate, saying they are sorry or something else, just as empty and meaningless; bipolar symptoms it seems here.
This is also were the "mixed" messages come into play; where they will actually say one thing, and end up doing another or even the opposite....and the thing is, again, you NEVER know for sure what will happen with them from one day to the next...half of what they do will seem sincerely geared toward trying to work on themselves, and at times, you think they are really making the effort, while the other half is confusing as all get out. Or they will make an effort, but actually get it "half done" or even withdraw to process at the halfway point of being in action.....I've SEEN this happen more than once....it's been said that good intentions have many times paved the way to Hell; and most MLC'er's THINK they have good intentions, but their follow up is as slow as their "giddy up"...because the STARTING HALF of the actions is the INTENTION spoken out loud...as you can't read their minds....then as you watch for their actions, these can go either way, depending upon where they are within the crisis, or even depending on what's in their minds, and you never know.
Others may appear to want the relationship one day, discard it AGAIN, the next day or even week; they really DON'T know what they want during this time..it's like a child with so many toys he/she doesn't know what they want to play with, and the vast majority, God help us all, get SO cranky you think they need a nap 24/7...acting like babies with belly aches or even colic....or better than than, they are suffering "growing pains".
And with some, well, you have to watch them closely, or your house will burn down, no kidding...they are absent minded, not half conscious of what they are doing when they are doing it...the fog is SO deep within themselves, I could remember being very surprised when some things would actually get done all the way through, and it did happen sometimes.
This is ALSO where expectations need to drop to zero and below..if they speak an intention and follow through, even halfway, that's great; but don't become a "glorified" babysitter for them..protect yourselves where you need protecting; because in the end, YOU are the sane one, they aren't, you know what's going on, they really don't for most of the crisis.....and above all, please learn to let them go to twist in the wind; sometimes that is the ONLY way to help them come forward is by leaving them alone; remember, you can do NOTHING for them, to them, or because of them.
One last thing to remember NOTHING is EVER as it seems; especially during MLC.