["Esteemed company"? Suspiciously cheery message? Monsters? Clearly there is only one explanation.]

This area appears to be overrun with bio organic weapons.

[For a new person, Leon looks and sounds quite composed, albeit tired. This is slightly weirder than the situations he usually finds himself in, but not by much. He's not going to think too hard about it just yet, especially considering there may be others in danger.]

If you run into one, do not attempt to engage in combat. All survivors should report to S3217 immediately.

[He sure sounds like he knows what he's talking about — of course, he actually has no idea what's going on. Or what that place is. But he found a paper with that information and assumptions like these have worked out well for him in the past, so hey, why not?]

I'll secure the vicinity in advance. Stay calm, we'll get through this.

[Your hero has arrived!
...except, y'know, not really.]