Tyr's Hand is the classic case of a Card, that looks really powerful on first sight.
You break that ETR? No, I think not! Steal averted, Agenda safe.
I was very surprised not to see it played more often, so I started looking for the reason and found it in the FAQ:
The Subroutine, prevented to be broken, can be broken again in the same Run!
So unless the Runner didn't calculate very thightly (what would be stupid anyway with an unrezzed Upgrade in the Server) he can simply spent that additional or and the Run continues. The only Ice, that could be useful here is Heimdall 2.0, where the spendable Clicks are limited.
If they added the 3 little Words "for this encounter" at the End of the Text, this Card would really be powerful.
But they didn't...