I agree that it is on panel that Synch reached out to the Professor, but ECloak further suggests or thinks that just because Empath did not reach out, Xavier or Emma with cerebro cannot pick him out on Krakoa..Which I feel is a really tall claim.Since when was reaching out a prerequisite for backup? If that were the case then it means once a week life on Krakoa stops for all for a moment or for a moment every day a mutant has to stop what they are doing and reach out to Xavier to have the backup done.Is this realistic? I mean this is fiction it is possible but what is more likely is Xavier does the backup without requiring any sort of 'communion' .Besides we have seen cerebro find mutants all over the world, lock onto them when they don't even know they are being looked for..
This is how Beast describes Xavier using cerebro in Wolverine 3 :
' I'll admit some jealousy at the sensation he must experience each time he places Cerebro over his head.I imagine the gentle quake that must run through his body,almost seismic as he expands a whole world growing inside him.A mindscape he can travel to seek out each and every mutant. But here is what matters ,when he searched for the one everyone call pale girl..he couldn't find her'
From this it is safe to say Xavier can find mutants even if they don't call out to him and secondly only a mutant that is either a really skilled telepath or one with an unknown but telepathy proof mutation can hide from him with Cerebro.
Yet we are supposed to believe Empath cannot be seen by Xavier or Emma on Krakoa especially when he is part of a team sent to a cerebro impervious zone?..suddenly the Hellions are not being waited for by Xavier/Emma to not only help them survive or even to glean fresh intel from them as soon as they arrive? That is just inconsistent with how ready and prepared for updating and resurrection the vault team was in X-Men 19 to suggest the Hellion team was entirely missed. Sure Sinister covered his tracks with the smoke but does he have the pull to cover his tracks with cerebro? More likely than not Emma swept it all under the carpet because she was 'onto him'. Otherwise he would be found out and outed a long time ago.