Midnight on the Firing Line

[Sinclair enters Kosh's quarters. Kosh is not in his encounter suit. We see a moving ball of light behind a wall]

KOSH: Greetings, Commander.

SINCLAIR: You weren't in the council room earlier. I wanted to make sure you knew about the emergency session.

KOSH: Yes.

SINCLAIR: We may need your help to push through sanctions. Does your government have a position on the current situation?

[Kosh does not answer]

SINCLAIR: Will you attend the emergency meeting?

KOSH: Yes.

[Sinclair wants to leave. As he turns his back on Kosh, Kosh quickly slips into his encounter suit]

SINCLAIR: Who, the Narn or the Centauri?

KOSH: Yes.

As it happens, Kosh's "yes" at the end wears off with time. I guess it would have been better, though admittedly less enigmatic, if he had simply said "both".
Apart from that, I was surprised how much of the real Kosh we already see in this first episode. I wonder what he was doing behind that semi-transparent wall. Taking a shower, perhaps?