Broke a timing cover bolt

The oil gallery is a bit below and to the left of the cam in your pix, and the only upwards oil passage is back at cam bearing #4. So it should not be in an oil passage. The water jacket should be an inch or so off to the right.

You would be well advised to: Pull the valve cover and I think you will see this hole going into the front-most pushrod gallery, which would explain the oil nature of the space behind the bolt hole. Then clean out any drilled metal as best you can so it does not go on down into the pan and work its way back up into the pump and the rest of the engine...ow! There should be only the relatively low crankcase vapor pressure behind the bolt so seal with some blue locktite or teflon tape, IMO.