When a suicidal crisis is suspected, stay calm, stay with the suicidal person and ask another person to get as quickly as possible?

This statement is true.
You should always stay calm if this happens, because if the suicidal person sees you panicking, you are going to trigger them even more and they might actually commit suicide. You should never leave them alone, because they are probably lonely and need people around them. Somebody should get professional help as soon as possible to aid them.