[It doesn't matter to Baymax whether or not his target recognizes him, in fact, he might have just assumed that Callaghan had realized it was him as soon as he came into view. With his scanner and Hiro's orders, he could spot Robert no matter where he was.

When the microbots crash against him again, he responds as he did before, with a large, heavy fist taking the brunt of the blow.

If he was programmed for anything other than karate, he might note that these microbots were acting somewhat different than the ones that had built his armor, Callaghan's current swarm was more instinctive and in tune with their master. It's a stark contrast from the directionless horde that had floated with him through the void.

Once the rush of microbots slows, he continues his destructive climb upwards towards his objective.]