What does she say in this video?

Question

Bokusatsu Tenshi Dokuro Chan Season 2 EP1 5:16

I think she says something like 読んでこようだ or maybe 呼んでこやった. I'm just a beginner. I can't make out exactly what she says.

Answer 1

She clearly says:

[呼]{よ}んでこようっと。

呼んでこよう is the volitional form of 呼んでくる (呼んで + subsidiary verb 来る).

For 「Volitional + っと」, please refer to this thread: What does volitional form + っと mean?

Answer 2

It sound like you are asking what is said directly after ～と一緒に入る, while she is in the process of standing up.

To me, it sounds like she is saying「呼んでこようっと」, as in 呼んで来る. Which means that she will go to fetch Zakuro-chan.

There are certain utterances that people say when lifting heavy objects, forcing themselves to stand up, etc. (basically grunting). In Japanese these can sometimes take on a highly individualized manner. Some common ones, however, would be 「よいっしょ」and「よっこらしょっと」. I've also heard 「どっこらしょっと」. In other uses, adding っと to the end of a phrase can be a spoken self-motivating tool.

It seems like while in the process of standing up she is saying 「呼んでこよう」while adding the 「っと」in demonstrating the physical exertion utterance or willing herself to action.