Most likely a server that was hacked, most people appreciate getting a call at that point to let them know that they are hosting something that is not entirely kosher.
That seems an awful lot more like a, "shit, someone's connected the dots" response. Especially if you're claiming ignorance about the domain name being called about. 15 seconds isn't even long enough to walk down the hall and ask someone about it.
Even if not a literal 15 seconds, the phrase doesn't seem to imply that there was a length of time where someone on that end might have been investigating the issue. It implies that someone flipped the switch to "off" the instant one was able to get within reach of the switch.