Is it possible his arm got blasted off? Because we’ve seen Rhodey fall from the sky with damage to his arc reactor and a very P.O.’d Tony. Tony would probably learn from this event and prepare for the same to happen to him. 

Then we have seen Bucky attempting to rip out Tony’s arc reactor. 

Isn’t Tony’s suit capable of firing from that arc reactor? He wouldn’t really need to physically rip it off…

I am too tired to work out if I have the sequence of events in the correct order.