Warp cores are a frequent plot device in Star Trek, as well we all know. This question has a list of ejection events and a nice picture of what appears to be a warp core coming out of Voyager. Apparently there are 7 successful and 14 failed attempts to eject a core shown in the canon.
I found myself wondering what an engine room looks like without its warp core. The core is the centerpiece of nearly every Engineering set. Examples:
There are many shots of cores overloading, in the act of breaching, online, idle, offline etc. etc. At the end of First Contact, you even see some footage of the Enterprise-E warp core being brought online after suffering a total loss of coolant. It seems like it would be a very striking visual to show a core being ejected, or at least a before & after shot of engineering. It seems odd to me that I can't recall ever seeing an engine room without its core.
So my question is: have we ever been shown such a shot? If we haven't, what would it look like? Just a big empty room? Or is the core on some warp drives inside the big center structure we see in the engine room?