[The guy just. Shrugs, honestly?]

You'll know once it takes effect. It shouldn't take too long to kick in, not with what we've been doing with it.

[The injection he's preparing is large-bore, as far as the needle goes; this is probably not going to be terribly pleasant.]

It might be a little jarring. But it's the sort of thing that you should just let happen; it'll be easier on everybody that way.