This is probably more fore for people who've never taken lorazepam and are curious than people who have (since anyone who has can and should refer to your own experience to know how it's likely to work or not work!):
My data set is admittedly extremely small and anecdotal, but I've noticed lorazepam can be very inconsistant at prescription doses (no personal experience with anything larger).
My mother takes it for anxiety. She's much heavier than me, has been taking it longer, and is on a smaller dose, but it's mostly effective for her save for when she's very stressed - and then she has the option of taking a second because her prescription provides for two a day. She often takes it to help her get calmed down enough to be able to do whatever it is she's putting off doing due to anxiety, but ends up falling asleep instead. She's been able to get it fairly easily because she's in mental health treatment and takes it for mental health reasons.
I take it as a sleep aid, because I'm neurodivergent and have paradoxical reactions to most psychiatric meds and "regular" sleep aids, and benzos are literally the only thing that don't send me into a terrifying spiral of craziness (and I actually like a lot of my innate crazy, so that's how bad it is - even *I* don't want it). But at best, lorazepam might help, and at worst, it might nudge me toward hypomania. I don't really enjoy the hypomania because I'm still awake, but I have the stereotypical "mentally ill artist" hypomania, where I get super-creative, and it's definitely better than full mania (which I will 100% end up in if I don't sleep - looove the cycle there -.- ), so the risk vs reward factor is more worth it to me with lorazepam than the other things I've been on. When it works the way it should, I feel a little floaty before drifting off (I personally don't enjoy it as "oh boy, I'm high!" because I don't like things that mess with my head, but I used to have a "yay, I'm going to be able to sleep!" association with it, and that was nice). However, I've sometimes had difficuly getting it because I'm NOT in mental health treatment and refuse to subject myself to it just to get a sleeping pill (I have PTSD from forced "care"), and the full-service clinic I went to when I first moved into this area, for example, classified it as "psychiatric only" and wouldn't allow it for any other reason.
I also build up tolerances incredibly fast. Benzos are tolerance-building anyway, but my personal tendancies are above and beyond that (to the point that I've had people suggest I'm lying. With some of the "failed in that they didn't make me crazy but also didn't knock me out" meds, I've been told, "Well, it's because you need to take (whatever) every day for it to work, but if I do that, it will stop working. I know that because I tried it). Right now, I'm taking 1mg of lorazepam, 50 mg of hydroxizime pamoate (Vistaril, an antihistimine with supposed anixety-reducing and sedating properties), 25mg of promethazine (Phenergen, an anti-nausea medication with sedation as a side effect), all prescription, with 50-100mg of diphenhydramine (Benedryl) and 50mg of doxylamine (Unisom) OTC on top, on pretty much a daily basis. I might go to sleep after a few hours. Maybe. If I'm lucky. I'm told that lorazepam is supposed to take 15-30 minutes to take effect, but even when I was only taking it occasionally and didn't have this level of tolerance, two hours was about the fastest it ever kicked in. Sometimes it's more like four to six. If it does at all.
Because my prescription is for one a day and I can't get it filled more than two days early, I have a VERY limited ability to take an extra no matter how badly I need it. If I take 2mg at once, I might sleep. If I take 1mg to start and another 1mg later, I'm more likely to stay awake for 24-36 hours (or more), which is akin both to what I'm prone to doing without medication or when I'm manic, and what happened when I tried Rozerem (specifically a sleep aid, that works on a different set of receptors than Ambien/Lunesta/etc). I don't want to ask for more (whether in the way of "more pills" or "higher dose per pill") because I know a lot of doctors are leery of it and I'm terrified of being seen as med-seeking to feed an addiction and having it taken away entirely, even though I've been told I'm on a lowish dose and given how averse I am to ANY kind of medical intervention (I turn down most things I'm offered, no matter what they're for, look for doctors who'll let me slide on the bare minimum of tests and appointments, and refuse any tests or treatments I'm allowed to refuse), it's probably not all that likely I'd ever be seen that way. But I'm too afraid to risk it.
When I had a friend I could source alprazolam (Xanax) from, I went from taking 1mg of either lorazepam OR alprazolam a day, switching off so when I started to tolerate one, I could use the other for a while, to taking 1mg of lorazepam AND 1-2mg of alprazolam daily. And sometimes I would sleep. Maybe. If I was lucky. I've also been able to access Xanax under the table more than once in my life, and the first few times, it was goddamn fabulous. The most recent time, it fucked me up. Bad. I had zero ability to recall my dreams (which might not be an issue for some people, but I'm very dependent on dreaming as "get out of reality" card), and on the rare occasions I did, they were always nightmares. I sometimes have panic attacks when I attempt to go to sleep because I have other conditions that interfere with my ability to drop off, and they got more frequent and haven't really regressed since I stopped taking it. (But if you handed me some right now? I'd still chance it because I'm so desperate to be unconscious).
I had a day a few months ago where, for various reasons, I was actually able to take 3mg of lorazepam, and oh my god it was amazing. I was out so hard. I had a day a few weeks ago where I was able to do it again, and nothing.
I know people who've been on ONE of the things I'm on and are out cold. It's goddamn hilarious to me to hear things like, "My husband takes 25mg of Vistaril and is a zombie", if by, "hilarious", we mean, "I laugh and then I sob". I've also been on klonopin and it did fuck-all for me, but as far as I remember, it worked at least passably for one of my friends.
The takeaway here is mostly, "If you've never been on lorazepam, I would probably not recommend depending on it as an SI blocker without being able to test how you react to it both at prescription and overdoses, and I would definitely not use it to try CTB on its own". When I was able to take it occasaionally, and especially when I moved out here and the clinic said, "Nope, you can't have it for that, but we'll give you a two-month wean-off prescription," and they didn't understand that I wasn't taking it every day, so they had literally handed me 120 pills to add to my "In case I work up the nerve" hoard, that's exactly what I did, was hoard as much as I could because I felt better knowing that I had it on hand if I decided to try, and when my hoard ran out and I couldn't build it back up because I legitimately needed to take it daily, it contributed a lot to how miserable I was (I mean, I still am, but it's for other reasons). And one of the things SaSu did for me was give me was the knowledge that it didn't matter, because it's not a good method anyway. So I can take it to knock myself out (...ha) without feeling guilty because I "should" be saving it up, AND I won't make the mistake of trying it and ending up in an even worse place because it failed. (Mind you, I'm not saying, "don't hoard it if it DOES chill you out and/or render you unconscious, and that's all you want it for". Just...know that it does before it's your last resort.)