[micmil]

No, and no.

The mantle is solid. You would have to drill way deep into the mantle before you encountered liquid rock.

Volcanoes don't work like that. Even if you drilled directly into a magma chamber, not much would happen. This has been done inadvertently a handful of times. https://phys.org/news/2009-06-scientists-drill-magma.html Basically volcanoes only happen when there's an extreme amount of pressure from below.