Oh yes. Very important. [He's not going to address the issue of not hurting anybody. It's true that the Celestial Intervention Agency avoids harming Gallifreyans (renegades excepted, but renegades are criminals and they deserve it). But other species? Not so much care is given to their wellbeing.]

The physics of this universe is different from those I know. Temporal technology doesn't work here, at least not any form of temporal tech I'm familiar with.