I noticed that too. What if Picard calls for warp power? And the warp core appears to not need a shutdown sequence or restart? So in Star Trek Into Darkness (but not ST'09 oddly), the ship loses power when the warp core goes out. So in TNG, if the warp core only powers the warp engines, then what powers the rest of the ship? Another plot hole is in The Drumhead. The warp core is out of service, yet the nacelles are glowing at the start.