Is the stealth vessel capable of maintaining its stealth mode while its airlock is open?
My thought is that the first "stop" could be near the bridge in order to let Mireska - and maybe some others - out (by opening an airlock facing in the direction opposite to the bridge). She could set some charges with some combination of timer and signal activation and then get back on board the stealth vessel for a drop off at the airlock closest to the Invincible's bridge with the rest of the bridge group as originally planned.
This way we have the option of having some charges go off even if we're not 100% successful with an "internal/shipboard" approach to the bridge. (I'm thinking of the opening scenes from Phantom Menace; if the emergency bulkheads/doors to the bridge are dropped, then an internal approach will be more difficult.)