That firewall cover plate has a rubber center that captures the tube and isolates vibration.
There is a similar plate on the blower motor. Niether rigidly fastened to the item they isolate. Just a tight slip fit,
Another member recently tried to jerk the steering wheel off the column and pulled the column apart at the box coupling because the tube will slid through the rubber collar.
A service manual contains all this and more. Free download too.