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I'll keep this short.
As it currently stands with herbs/minerals resetting to your inventory in the arena, things like riftlock are impossible to achieve there. Would it not be better for them to reset into your rift when eaten instead of inventory or is there a specific reason for the way it is at the moment?
I realise you can still get around this by out-rifting everything but being able to practice setups like this in the place where we practice would be of great use to people learning the ins and outs of combat.