systemctl isolate emergency.target

When running in multiuser.target, if I issue the command:

systemctl isolate emergency.target

The system hangs and it never transitions to the emergency target run level.

However, if I issue the command:

systemctl isolate rescue.target

It does transition to the rescue.target run level

So my question is:

Is that not a supported procedure? To go directly from multiuser.target to emergency.target without rebooting?

thank you.