Not sure how the valves bent yet...ideas?

Friend roasted his engine. 1997 Honda accord w/ F22b2 engine.
Head gasket blew and head was severely warped.

Had the head pressure checked and resurfaced.
put everything back together with new water pump and timing belt kit.

Drove excellent during test run for about 2 miles.
After maybe 8 miles, engine went out.
Thought it was out of gas actually, but after doing a leak down test...found 30-45% leakage on the cylinders.

I reset the valve lash but even if they were a little tight i dont see that being the problem.
If the machine shop took way too much off the head i can see that causing the valves to smash into the piston but MILES DOWN THE ROAD???

Did i just have a timing belt jump or is it even possible to have the car go a ways before the valves bend?? due to improper clearance?

I manually turned the crank close to 20 times to check that there was no interference, i've never bent valves because of a messed up timing install...
and i don't believe that improper valve lash (just in case for some reason the sticker under the hood was off a few mm -- all data gave a slightly different lash setting) being too tight would cause the bent valves...

 

No clue, not sure what a 97 Accord is.