Why do I have an invisible bomb?

I'm doing the Tuchanka: Bomb mission and I seem to have arrived at the location of the bomb. However... the waypoint for it is floating in the air above Shepard's head and there doesn't seem to be any bomb there.

This is what it looks like from a few paces away:

I've searched the immediate vicinity, but I don't see anything else to interact with here. What can I do?

The bomb is outside, the waypoint is accurate. You've got to make your way outside. If I recall correctly, you have to climb up some ramps and you make your way outside.

The waypoint system isn't great, this is a case where it's making a longer-term goal visible instead of saying "Head in this direction!"

I found an abstract sketch as to try to minimize spoilers

Don't worry, you won't miss it. Try to keep exploring.

Those markers do not take walls into account, it's most probably behind it. They mark the location in a straight line from you.

They are generally all this bad (for not saying almost useless), and they require some getting used to.