[Wrattleham]

While he is inwardly rather nervous about the fellow with the gun, he doesn't show it and it isn't for the usual reason people get nervous about having guns pointed at them.
Spontaneously being fired upon would be a pretty nasty block mark on the "xenophobic" charge and would probably nudge him towards taking actions he doesn't want to.

They could still just be people. Albeit mutated.

Not being shot at, but being aimed at is fine, if they haven't had much contact with outsiders though.
It's tempting to smile down at the man, potentially put him at ease, but it could ruin the experiment.

From this point of thought, after staring into the windows, Xeni looks for the nearest door into the room. Hopefully it's exterior access, otherwise he's going to have to scare the people a lot more when he pulls on some magic to phase through the wall.
One way or the other, his goal is to make his way into the room and greet everyone in the least threatening way possible: a very stupid grin and dorky half-wave with one hand.
"I come in peace!"

This is probably going to be significantly less funny looking if he has to do it after phasing through a wall.