raywest

Question: Why does Benji have to enter the facility at the same time Ethan is switching the security profile? It's more dramatic that way, but couldn't Benji have waited to enter until after he knew the profiles were switched?

Answer: He most likely could have waited, but as you pointed out, it's more dramatic that way. This is a movie and the action is choreographed for maximum dramatic and visual effect, timing, tension, continuity, audience attention, and character interaction. We're not supposed to overthink it.

raywest

They would want Benji to enter as soon as possible, as the security may notice eventually that there is something amiss. Still going in without bothering about confirmation seems unnecessarily risky.