Oil pump priming issue

So I was using a drill on my 318 to prime the oil pump and oil is gushing up through the oil pump drive hole.

I've done dozens of small blocks and never seen this before.

As everyone knows the pump is literally bolted into rear main cap from the bottom with the drive flange basically press fitted into the main cap, and oil pump drive goes in through the top from the valley, so where can oil come up through the oil pump drive hole?

I suspect the oil pump has failed in some way or come loose. Any other suggestions?