I would use commas before and after 'basically', but I agree with Chenmunka that the word "basically" is one of those verbal tics that people have nowadays that mean nothing. It's like "you know" and "like."
So take it out, unless it's a quote from someone who talks like that.
The emoji is the punctuation. Regardless of what rules we might try to put on chat grammar, the zeitgeist will decide in the end. It does exactly what punctuation would do in many cases. It can end the sentence, express your excitement or confusion, as well as communicating that you're asking a question.
Your punctuation doesn't seem right. I won't say it's wrong because there's probably some case for it in English, but as a reader, the dashes and the run-on sentence confused me.
This is how I'd done the punctuation in your example.
“Well, since you guys didn’t stop when I assume you heard the shots,” he said, motioning toward Dempsey beside him. “......