Throughout the 10K years from now on, hazardous atmospheres probably won't be an issue, because of robotics - which wasn't even an imaginable option for the most part of the last two millenia (and now we're rapidly getting good at this stuff, so I somehow doubt Qin Shi Huang's tomb would remain unexplored for long).

Even if we could enter the Qin emperor's tomb unharmed, we should leave it untouched out of respect for the dead.

From my understanding, the reason it hasn't been opened yet is to preserve whatever's inside, not so much out of fear for mercury poisoning. For instance, the terracotta army was actually painted before it was excavated [1], but the paint curled and flaked off within minutes of opening the mausoleum, leaving us with a sea of drab stone statues. I think they're just waiting until they have the tech to properly preserve the interior.

[1] http://www.chinadaily.com.cn/china/2010-09/09/content_112783...

I would enter it. (And he wasn't the first emperor. He was the first emperor of the Qin dynasty)

I would enter it.