Your grip on his hand tightened as you braced yourself and you moved
your other hand back up again, finally plunging your fingers deep into the
tangle of wires. You could feel the pulses of electricity moving through
some of them and the hum of his internal fan was much louder with his
chest open like this. Mettaton's eyes shut tighter as a hiss escaped him.
Now more confident that you weren't going to hurt him (in fact, you
seemed to be doing the opposite), you closed your own eyes as you felt
around inside his chest, trying to determine which wires should be placed
where in order to better fit.