"Jane thinks that under normal circumstances you being immortal is fine but suspects you might have unfortunate fracture points under particularly earthshaking circumstances. The correct response to earthshaking circumstances, now that we have met, is not 'try to make the earth stop shaking with telepathy and magnetism', but 'summon a Bell or someone else with similar wherewithal to fix it by magic'. Jane herself is not totally reliable, or at least hasn't been in the past - we've patched the known failure mode - but that's not a big enough risk to actually insist that you go on being mortal."