I'm Japanese, and have relativery better English speaking ability than average Japanese...

I can comunicate English speaking players, but always I'm not sure my expression is right.

For example, when I went out Wajaom to kill Colibri for my Magian Katana, a BST player joined with us. Off course he needed to let his Nazuna kill Colis. At that time all party member is Japanese, so Nin and Thf tried not to kill enemies, just remained a little HP and let his Nazuna kill them.
After a while, an English speaking Nin joined with us, and he didn't realize about this, killed Colis himself.
So I talk him "Please let Nazuna kill Colis", and he understood, he also remained a little HP for Nazuna.
Yes, he can understand my English, but I'm anxious that it sounded rude, or there might be more suitable expression...
(Auto-translation is usuless for these cases.)
In Japanese, in this case it is expressed like "Pet(Nazuna) sime onegaisimasu".

Could you tell me the better expression about this case?

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Other case, it happens many times, two or more party copete against ??? in Abysea.
And when one party consists of Japanese, and other party consists of English speaking peoplle, it tends to become "Firs trade pop item, First served", unless English speaking Japanese exists in Japaese party.
(And Japanese people complain "Gaijin is selfish!", and Engish people complain "Japanese is selfish!".)

When I meet this case, I say "Take turn, please?" and it is understood.
We can pop NM in turn in a peaceful manner.

Is it a good expresson? Is it sound rude? Or is there better one? if so, could you tell me.
In Japanese, this case may express "Kougo ni onegaisimasu."

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And if you have some expression that there is not in auto-translation and you think let Japanese know, also tell me with situation.

I think misunderstanding between Japanese and non-Japanese people comes from these kinds of littile conflict, so to resolve it, I wait your thinking and feeling.