Equipping in the demo does not interrupt your spell. You can cast a spell, equip and start loading a swing/fight. This is what actually makes Pre-T2A combat work, because there is a large equip delay in Pre-T2A.
If I remember correctly, the implementation of equip-disrupt was based off of majority opinion, there was no evidence either way. Correct me if I'm wrong, curious as to what is really behind our mechanic on it.
As another small note, earthquake damage (from quick glance) appears to do half the damage of a victim's maximum HP (if they aren't a NPC), which would tend to be 50 rather than the 60 we see here.
EDIT:
Discussion during the re-implementation of precasting (UOR)
http://groups.google.com/group/rec.game ... +interrupt#you do need hands free to cast
> the spell. Re-equipping during the casting will interrupt the spell.
> After the spell is over, you can re-equip the weapon."
http://update.uo.com/design_346.html