I would think that the 50 Navy SEALs would be a joke to Ult. Cap. surprised to see so many people think that particular round would give him enough pause.
Man went through SHIELD superforces and Machine Men and Nick Fury while tranq'd, and surprised and without his shield and with Bucky to worry about. Only reason he got taken down then was because of a particularly sneaky Machine Man flying blitz, which none of the Navy SEALs would have.
I think he stops around the time he gets to Thing. He'd be exhausted by that point int he fight.