PotP DotM Sentinel gestalt!
https://i.imgur.com/A8R7hjf.jpg
Sam Witwicky: [to Lennox] We gotta get Sentinel outta here, he is the key to all this...
Sentinel Prime: Indeed I am!
https://i.imgur.com/lMxBD8r.jpg
(transforming noise) What you must realize my Autobot brothers, is we were never going to win the war!
https://i.imgur.com/ZZGJrGY.jpg
For the sake of our planet's survival, a deal had to be made...
https://i.imgur.com/IV2Wm0u.jpg
... with Megatron!
https://i.imgur.com/QEepCD9.jpg
Ironhide: [rusting away] Sentinel... what have you done?
Sentinel Prime: [to Ironhide] I hereby discharge you from duty!
https://i.imgur.com/WLsWm0P.jpg
https://i.imgur.com/lrpePSS.jpg
https://i.imgur.com/JGJoOnJ.jpg
So in my head canon Sentinel has betrayed the Autobots so that when he combines he becomes a Decepticon! The Autobots he combines with have no memory of this....
To me it's in line with Dark of the Moon
The gestalt head is a FoC Ruination head with the antenna removed.
