[Snake]

'On My Mark' being able to be toggleable is essential for Tacticians and shouldn't be changed. Especially in situations the Tactician needs to be slower than the fastest person in their team. (Not saying slowest.)

I say make it a toggle skill, but not an 'on/off' type. Make it grant you the On My Mark status effect which gives you a buff with the passive's effects while you're inflicted with it, and if used again, it will toggle off. This should also cost 1M.