Since it's instructive (this thread may be longish):
B: "I am secondary on [an emergency / a drill] for [area]. Here is the book."
A flips to Page 1 and reads down a checklist in order.
A: "I am attempting to log into [production / test] environment."
A: "Login complete."
B: "I verify you are logged into production. Proceed."
A: "I am queueing up an alert, entitled $TEXT."
B: "Confirm to me that your expected text is [reads screen]."
B: "I acknowledge you will send the alert to $GROUP."
A: "I have selected $GROUP in the interface. Confirm."
A: "I will now send the alert."
B: "You are good to send the alert."
A: "I have sent the alert."
We thought about this process *a lot*, and drilled it.
Well, technically, a binder, in case we ever needed to update procedures.
"Why not have it on an electronic system?"
Because binders have 100% uptime even if office/remote servers/etc are presently rattling in the wake of e.g. earthquake.
This is a question that gets perilously close to that I Can't Tell You territory, but web developers who have ever coded "Fire X if we don't get a heartbeat from Y" can probably guess.
When it really counts, there are only two teams: humanity and disaster. We’re all in it together on Team Humanity.