It sounds like your starter just choose this time to exit stage left. Highly unlikely that it is related to the seafoam.

BTW, did you get anything out of the cylinders? Hydrolocked means that there is enough liquid (non-compressable) in the cylinder to not let it turn over. If you pull the plugs and turn the engine over, it should push out any fluid. If you really only sucked in 2Tsb then you did not hydro lock the engine.

Again, I think your starter just went TU. Check the batteries to be sure, but...it looks like it is time to pull it and get it tested.

Good Luck,
Michael