I am a Crisis Text Line volunteer. So the short answer is yes we do call EMS when we have to. I posted this longer answer in a different parent on this thread, but I'll re-post it since it directly speaks to your question and sheds some light on the criteria we use to determine if someone might harm themselves.

"...We are trained to risk assess each and every texter, irrespective of our intuition about their mental state. That means I treat someone testing the system like I would someone who has been flagged as an imminent suicide risk.

Supervisors monitor this evolution of the conversation closely.

The assessment is important because ultimately the decision to call emergency services comes after that rigorous assessment of the person's suicidal ideation, followed by their plan and access to means, as well as their timeline. If all those criteria are met, I contact my supervisor, and then we work on separation from means. If those criteria are not met, we continue the conversation accordingly.

I have personally walked numerous people back from the edge simply by talking to them and hearing them out; often times, texters deemed imminent risks are capable of staying safe that night after we have come up with a safety plan for them together. Calling EMS is truly a last resort and not an attempt to cast off responsibility.

In the cases when we do call emergency services, it is after we have exhausted all other options. It should be noted that access to geolocation is strictly limited to these supervisors, and in all likelihood is limited to a texter's phone number alone. It's not like they have a backdoor into AT&T, and the supervisor must make a call to emergency services directly. From what I can tell, very little information is given back to CTL. On occasion, I can see a timeline that EMS was dispatched but rarely do I ever learn about the outcome.

The success of the platform is that we can work with people to find them their own solutions. CTL was not a viable intermediary for calling 911."

I've volunteered nearly 300 hours, most of those were dead of night EST. I've spoken to several hundred people, and maybe a couple dozen have been flagged as imminent risk. Of those flags, I can count on one hand those who have required a call to EMS. Mostly, I'm able to come up with a safety plan with them and get them through the night.