seiyi = ?

[VathRas]

Kaltxì, ma smuktu!

I am a little bit concerned about this statement:
Irayo seiyi oe ayngaru nìwotx
I nearly understand it, only this seiyi is troubling me.
I find Jake says something similar when he kills yerik (if i hear good it's Oel ngati kameie, ma tsmukan, ulte ngaru seiyi irayo.)

I couldn't find this seiyi in dictionary so I tried to find some infixes here. I tried, but neither s<ei>yi nor se<iy>i make sense cause I could't find such words.

Oh, and just now i've found there's no iy infix, but ìy. But it doesn't change the fact I don't understand this word.

[wm.annis]

This is a special case for the infix ‹ei›.  Since two of the same vowel cannot run into each other *s‹ei›i would be illegal.  The -y- is inserted to separate them.

[VathRas]

So, if i get it well, irayo is noun, irayo si (or si irayo) is verb then, and then all verb infixes go into this si? And what about all suffixes and prefixes in this case?

[wm.annis]

So, if i get it well, irayo is noun, irayo si (or si irayo) is verb then, and then all verb infixes go into this si?

Correct.  And in compound verbs, too.  In the word to hope, sìlpey, the true verbal element is pey — all the infixes will go into that syllable, unlike plltxe, for which the normal first-position and second-position rules apply.

[VathRas]

Well, what I can say?

Irayo seiyi oe ngaru