Well not necessarily Bearcat!
For a crew member to initiate an evacuation (well in my airlines SOP's anyway...dont know about Iberias but assume they are similiar) it must appear clearly catastrophic...ie, cabin broken up, fire, anything with an immediate danger to life onboard etc. Now an aircraft at an unusual attitude does not essential mean "catastrophic" and in a situation like this it would not be unheard of to remain alert but await further contact from the flight crew which is essentially what appears to have happened here.
Infact the cabin crew should be applauded for not going gun-ho into an evacuation as you can clearly tell from the video that an urgent evacuation was not required meaning that it was all very orderly, passengers had time to prepare, the crew were able to assist instead of just push and emergency personnel were onhand at the bottom of the slide to assist passengers off and away from the aircraft. Who knows how many unnecessary injury's were avoided as a result of this!
You guys may get a lot of stick but on this occasion.... well done Ibera Cabin Crew!!!!