No, it’s the computer’s beeping because Kogasa’s face is stuck on several keys for quite a while. The “keyboard buffer full” beeping was more popular back in ye olde days, though.
I'll let you off with only half-killing you, since we'll be in trouble if that art doesn't get done.Sure Enough!What the heck is this!? There's nothing done!!Are you going to make it on time at this pace!?Mrmm! Uummn!Not to worry!Here's where the miracle happens!Snappy'Cause I've got you with me, Sanae!Pi-pi-pi-pi-
pi-pi-pi-piKogasa...If you'd drawn every day like you should, you wouldn't need a miracle!