Exactly what a murderer would say.

[No, he's not setting Keats down. If anything, his grip is getting tighter to ensure the other can't get away.]

You were sleep-walking, gorgeous. Talking about medical records and investigations. You were adamant about denying an old identity and then you said you needed to be strong to destroy people. Is this what you're hiding? Is this the scoop we've all been waiting for...?

[It's hard to tell whether Mettaton's teasing or genuinely interested to find out if his friend is a serial murderer. Both. Maybe a bit of both.]