Imagine that you're suddenly thrust into a situation wherein you have to talk down a suicidal person, no one else is around, and time is of

Maybe. 

I don't know if any of you guys know this, but that's one of the main reasons I was on AB. I loved the witty banter a whole lot, and that's what got me to the site, but the place was filled with depressed people and people in serious trouble. We don't get that here because there's no instant access, but there... there would be someone new every few days or I could see a shift in a regular member and know something was up, even if they weren't talking about it. So, I'd privately reach out to them in a message and talk to them about whatever was going on. I don't even know how many people I spoke with anymore. Most of the time, our messages would just taper off after they felt better about things. I might see them pop back in on the site later, so I'd know they were ok. There were two, though, who came back to me months later after going MIA who actually thanked me and said they had planned to kill themselves the night I reached out to them, and that they didn't because of my messages. That really meant a lot to me. 

That's not to say I'm an expert. Not by any means. I'm sure I miss the signs in people sometimes and there's a chance I really wasn't able to help some of the people I messaged. There's one in particular I remember. I do think he killed himself and I deeply regret not realizing how close he was to it. He was one of the long-term ABers- around prior to the '09 switch. He had some pretty deep issues and claimed to have been wounded in combat. He could have been a troll or a puppet, and sometimes I wish I had found even a grain of evidence that suggested he was, so I didn't feel like I let him down, but there was nothing. He was just gone one day. I sent him emails off-site, asked around... nobody knew where he was. That still haunts me. This post was edited by Just Asking at February 23, 2018 6:15 AM MST

Never been in that situation, so I couldn't say yes or no.
I suppose I could attempt to talk them out of it, by first inquiring as to what the problem is, and finding a solution.

Is that better than doing nothing at all? I'd like to think, no.
I mean, I'd gladly administer first aid at a car crash scene, or rescue someone from a burning dwelling, so why not talk someone out of taking their own life...