As best I can tell from looking at several tear-down pictures, that same pot-metal rod that works the switch ALSO is the pin that locks the steering-wheel.
It would be my fear that it could also break in such a way as to lock one's wheel while driving.
Mine has given me fair warning, as it has been real sluggish and stiff on really cold mornings the last several winters; it is just a matter of time before it strands me somewhere.
With the alterations I have already done, so long as the column will un-lock, I ?think? I could still drive it; I would just lose the heater/A-C, wipers, factory gauges, I can't think of anything else.
My turn-signals have been independent of the column and key-switch for years.
My 110-555 Leece-Neville requires no input whatsoever to function; it takes care of itself.
On my 1989 E350 column, the ignition key cylinder has a gear that engages the vertical steering wheel locking post.
If you can turn the key, the gear moves the vertical locking post downward and disengages from the locking holes in the steering wheel, even if the pot metal actuator is broken. That was the case in my repair. Multiple broken parts in the column may be a different situation.
The pot metal actuator is linked to, and receives movement from, the vertical locking post. A spring pushes up on the actuator, which pushes the vertical locking post up to engage the locking holes in the wheel. Turning the key rotates it's gear, which forces the vertical locking post down, which forces the actuator down, which forces a steel linkage rod down, which engages the starter.
It is a lot of linked mechanical movement, that really needs to be well lubed with grease. My problem was the grease had dried out, and became an adhesive, causing parts to bind up.
Just pulling the wheel, and the plastic turn signal plate, should allow enough access to clean out most of the old grease, and relube everything for another decade of smooth operation.