Will be interesting to read the report, choosing to continiue flying depends on the emergency. I dont have any experience in the 350, but i have had an hyd failure in an very old bell47 about 8 years ago. An yes it can happen to you in straight and level flight with you not having any clue whats going on. Used to instruct in the machine an hyd failure training where done daily, in my case there where quite violent low frq vibrations and it did not feel anything like hyd failure. Pulling the mixture solved the problem after 3 failed landing attempts. Looking at the 350, that tailboom is long and if you start loosing parts back there you are quickly running out of cg, hard to see on the pictures if the tail is intact. I have a couple hundred hours in Danish terrotoriy, flying vip between the nordic countrys, i always fly in my survival suit when crossing kattegat\skagerrak area. Do not know if they had survival suits yet, but should be asked when flying out of gliding distance at this time of year?