I do not know as I did not request a lock on it. Only the Administrator can lock a thread. The Moderators do not have the permission to lock down a thread.
I would suspect that it is lock second degree to content.
Suicide threats or other threats of violence against oneself may be reported to the Administrator and he will make the decision to lock a post on the info received or after reviewing a thread.
"The real voyage of discovery consists not in seeking new landscapes but in having new eyes." ~Marcel Proust