Can Gunther be defeated at the first confrontation?
After getting out of train station, I happen to confront Gunther (surrounded by UNATCO) with the decisions of surrender or fight.
I didn't have enough of my arsenal, one missile and one LAM grenade. I sometimes die by shooting the missile and by the looks feels as if he didn't get a scratch...
Can he be defeated in the named scene?
Solution 1:
No, the encounter with Gunther in battery park is one of the few instances, where you cannot kill a NPC. Gunther is invincible in this situation and the story will only progress once he got you.