Thank you for your question. Basically it can be activated. Note that you have to activate the counter trap in a chain to the activation of mirror wall.
i mean trap jammer was conceived as a conter for "Regretful rebirth, Michizure, Reinforcements and Castle wall from my perspective because these are 100% activated in any battle phase"
for mirror wall use fkn malfunction, it doesn't matter whose turn it is, it counter the card and cost 500 lp, that's it.
Heckofagame
GameA1
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