It really should be a joke. Who the hell offers the equivalent of a particle accelerator while relaxing with a cup of coffee? But even if Accelerator mostly uses his ability for destructive purposes, at the end of the day that's what it is, particle acceleration, and if anyone's going to find that useful in a scientific context it's going to be Donnie.

He does look completely unamused with Donnie's reaction, though that isn't surprising. "Hah," he replies, deadpan. "You're hilarious."