Loud bang
N1 spooling down
Nosedown trim required
N2 may or may not be good
high vibs
low fuel flow
low (or loss of) EGT
Low oil pressure, oil quantity dropping
both N1 and N2 spool down (the N2 ain't gonna work with the N1 not working).
EGT typically goes way up since the combustor no longer can hold the flame without pressure from the compressors. I'm not sure what the gage will show if the EGT probes went with the rear end of the engine.
Impossible to miss those symptoms, but the crew may have been working on it and hadn't sorted it out when they got the radio call. Of course there is no way for the crew to tell about the missing bits and I doubt that the symptoms match what some call "severe engine failure" in a simulator.