not true. air carriers are hesitant to say the word EMERGENCY over the air. The tower may at their own judgement declare the emergency and roll emergency vehicles. Some situations are too severe/time consuming for the Pilot to declare.
Two engines running, albeit with one at idle, is not an emergency condition.
Every aircraft type (a technical term) I’ve ever flown, the abnormal checklist for an engine vibration called for a reduction in power. If the vibration went away, the engine remained running - it kept extra electric, air, and hydraulic systems available. The pilots were highly trained to make a normal landing in this configuration.
As to the “evacuation”, I highly doubt it was an ordered evacuation. I suspect a passenger decided on their own to pop the exit. Otherwise all of the other exits except the right overwing exits and the main cabin door would have been opened with chutes deployed.
I’m waiting for more info.
EC
Hogwash on the time severe/consuming comment. How about Al Haynes in Sioux City. I would say that was pretty severe and time consuming, yet they declared an emergency. We’re taught Aviate, Navigate, Communicate in that order.